Nucleophilic catalysts for oxime linkage

Preparation of the Homobifunctional Linker NH 2 [OCH 2 CH 2 ] 2 ONH 2

The homobifunctional linker NH 2 [OCH 2 CH 2 ] 2 ONH 2

(3-oxa-pentane-1,5-dioxyamine) containing two active aminooxy groups was synthesized according to Boturyn et al. (Tetrahedron 1997; 53:5485-92) in a two step organic reaction employing a modified Gabriel-Synthesis of primary amines ( FIG. 3 ). In the first step, one molecule of 2,2-chlorodiethylether was reacted with two molecules of Endo-N-hydroxy-5-norbornene-2,3-dicarboximide in dimethylformamide (DMF). The desired homobifunctional product was prepared from the resulting intermediate by hydrazinolysis in ethanol.

Preparation of the Homobifunctional Linker NH 2 [OCH 2 CH 2 ] 4 ONH 2

The homobifunctional linker NH 2 [OCH 2 CH 2 ] 4 ONH 2

(3,6,9-trioxa-undecane-1,11-dioxyamine) containing two active aminooxy groups was synthesized according to Boturyn et al. (Tetrahedron 1997; 53:5485-92) in a two step organic reaction employing a modified Gabriel-Synthesis of primary amines ( FIG. 3 ). In the first step one molecule of Bis-(2-(2-chlorethoxy)-ethyl)-ether was reacted with two molecules of Endo-N-hydroxy-5-norbornene-2,3-dicarboximide in DMF. The desired homobifunctional product was prepared from the resulting intermediate by hydrazinolysis in ethanol.

Preparation of the Homobifunctional Linker NH 2 [OCH 2 CH 2 ] 6 ONH 2

The homobifunctional linker NH 2 [OCH 2 CH 2 ] 6 ONH 2

(3,6,9,12,15-penatoxa-heptadecane-1,17-dioxyamine) containing two active aminooxy groups was synthesized according to Boturyn et al. (Tetrahedron 1997; 53:5485-92) in a two step organic reaction employing a modified Gabriel-Synthesis of primary amines. In the first step one molecule of hexaethylene glycol dichloride was reacted with two molecules of Endo-N-hydroxy-5-norbornene-2,3-dicarboximide in DMF. The desired homobifunctional product was prepared from the resulting intermediate by hydrazinolysis in ethanol.

Detailed Synthesis of the Aminooxy-PSA Reagent

3-oxa-pentane-1,5 dioxyamine was synthesized according to Botyryn et al (Tetrahedron 1997; 53:5485-92) in a two step organic synthesis as outlined in Example 1.

Preparation of Aminooxy-PSA

1000 mg of oxidized PSA (MW=20 kD) obtained from the Serum Institute of India (Pune, India) was dissolved in 16 ml 50 mM phospate buffer pH 6.0. Then 170 mg 3-oxa-pentane-1,5-dioxyamine was given to the reaction mixture. After shaking for 2 hrs at RT 78.5 mg sodium cyanoborohydride was added and the reaction was performed for 18 hours overnight. The reaction mixture was then subjected to a ultrafiltration/diafiltration procedure (UF/DF) using a membrane with a 5 kD cut-off made of regenerated cellulose (50 cm 2 , Millipore).

Preparation of Aminooxy-PSA Employing a Chromatographic Purification Step

1290 mg of oxidized PSA (MW=20 kD) obtained from the Serum Institute of India (Pune, India) was dissolved in 25 ml 50 mM phosphate buffer pH 6.0 (Buffer A). Then 209 mg 3-oxa-pentane-1,5-dioxyamine was given to the reaction mixture. After shaking for 1 h at RT 101 mg sodium cyanoborohydride was added and the reaction was performed for 3 hours. Then the mixture was then subjected to a weak anion exchange chromatography step employing a Fractogel EMD DEAE 650-M chromatography gel (column dimension: XK26/135). The reaction mixture was diluted with 110 ml Buffer A and loaded onto the DEAE column pre-equilibrated with Buffer A at a flow rate of 1 cm/min. Then the column was washed with 20 CV Buffer B (20 mM Hepes, pH 6.0) to remove free 3-oxa-pentane-1,5-dioxyamine and cyanide at a flow rate of 2 cm/min. The aminooxy-PSA reagent was then eluted with a step gradient consisting of 67% Buffer B and 43% Buffer C (20 mM Hepes, 1M NaCl, pH 7.5). The eluate was concentrated by UF/DF using a 5 kD membrane made of polyether sulfone (50 cm 2 , Millipore). The final diafiltration step was performed against Buffer D (20 mM Hepes, 90 mM NaCl, pH 7.4). The preparation was analytically characterized by measuring total PSA (Resorcinol assay) and total aminooxy groups (TNBS assay) to determine the degree of modification. Furthermore the polydispersity as well as free 3-oxa-pentane-1,5-dioxyamine and cyanide was determined.

Preparation of Aminooxy-PSA without a Reduction Step

573 mg of oxidized PSA (MW=20 kD) obtained from the Serum Institute of India (Pune, India) was dissolved in 11.3 ml 50 mM phosphate buffer pH 6.0 (Buffer A). Then 94 mg 3-oxa-pentane-1,5-dioxyamine was given to the reaction mixture. After shaking for 5 h at RT the mixture was then subjected to a weak anion exchange chromatography step employing a Fractogel EMD DEAE 650-M chromatography gel (column dimension: XK16/105). The reaction mixture was diluted with 50 ml Buffer A and loaded onto the DEAE column pre-equilibrated with Buffer A at a flow rate of 1 cm/min. Then the column was washed with 20 CV Buffer B (20 mM Hepes, pH 6.0) to remove free 3-oxa-pentane-1,5-dioxyamine and cyanide at a flow rate of 2 cm/min. The aminooxy-PSA reagent was the eluted with a step gradient consisting of 67% Buffer B and 43% Buffer C (20 mM Hepes, 1 M NaCl, pH 7.5). The eluate was concentrated by UF/DF using a 5 kD membrane made of polyether sulfone (50 cm 2 , Millipore). The final diafiltration step was performed against Buffer D (20 mM Hepes, 90 mM NaCl, pH 7.4). The preparation was analytically characterized by measuring total PSA (Resorcinol assay) and total aminooxy groups (TNBS assay) to determine the degree of modification. Furthermore the polydispersity as well as free 3-oxa-pentane-1,5-dioxyamine was determined.

Preparation of Aminooxy-PSA without a Reduction Step in the Presence of the Nucleophilic Catalyst m-Toluidine

573 mg of oxidized PSA (MW=20 kD) obtained from the Serum Institute of India (Pune, India) is dissolved in 9 ml 50 mM phosphate buffer pH 6.0 (Buffer A). Then 94 mg 3-oxa-pentane-1,5-dioxyamine is given to this solution. Subsequently 2.3 ml of a 50 mM m-toluidine stock solution are added to this reaction mixture. After shaking for 2 h at RT the mixture is then subjected to a weak anion exchange chromatography step employing a Fractogel EMD DEAE 650-M chromatography gel (column dimension: XK16/105). The reaction mixture is diluted with 50 ml Buffer A and loaded onto the DEAE column pre-equilibrated with Buffer A at a flow rate of 1 cm/min. Then the column is washed with 20 CV Buffer B (20 mM Hepes, pH 6.0) to remove free 3-oxa-pentane-1,5-dioxyamine and cyanide at a flow rate of 2 cm/min. The aminooxy-PSA reagent is the eluted with a step gradient consisting of 67% Buffer B and 43% Buffer C (20 mM Hepes, 1 M NaCl, pH 7.5). The eluate is concentrated by UF/DF using a 5 kD membrane made of polyether sulfone (50 cm 2 , Millipore). The final diafiltration step is performed against Buffer D (20 mM Hepes, 90 mM NaCl, pH 7.4). The preparation is analytically characterized by measuring total PSA (Resorcinol assay) and total aminooxy groups (TNBS assay) to determine the degree of modification. Furthermore the polydispersity as well as free 3-oxa-pentane-1,5-dioxyamine is determined.

Preparation of Aminooxy-PSA Reagent

An Aminooxy—PSA reagent was prepared according to the Examples 4-8. After diafiltration, the product was frozen at −80° C. and lyophilized. After lyophilization the reagent was dissolved in the appropriate volume of water and used for preparation of PSA-protein conjugates via carbohydrate modification.

Evaluation of the Efficacy of Different Alternative Nucleophilic Catalysts

rFIX was incubated with sodium periodate, aminooxy-PSA reagent under standardized conditions (1 mg/ml rFIX in 20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 ), pH 6.0, 5-fold molar aminooxy-PSA reagent excess, 100 μM NaIO4) using different nucleophilic catalysts (aniline, m-toluidine, o-anisidine, m-anisidine, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, p-aminobenzamide, sulfanilic acid/standard concentration: 10 mM) The reaction was carried out for 2 hrs in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of aqueous cysteine solution with a final concentration of 1 mM.

The coupling efficiency was determined by SDS-PAGE using an Invitrogen X-cell mini system. Samples were spiked with lithium dodecyl sulfate (LDS) buffer and denatured for 10 min at 70° C. Then the samples were applied on 3-8% TRIS-acetate gels and ran at 150 V for 60 min. Subsequently the gels were stained with Coomassie.

In addition the samples were characterized by use of a SEC-HPLC system using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77).

50 μl of samples were injected undiluted and eluted isocratically with a 0.22 μm filtered solution of 20 mM NaH2PO4, 50 mM Na2SO4, pH 6.1 at a flow rate of 0.5 ml/min. The elution pattern was recorded at 280 nm.

The results are summarized in FIGS. 5 A-C and 6 (SDS PAGE) and Table 2 (SEC-HPLC results). The catalytic effect of the different preparations is demonstrated. It is shown that the use of m-toluidine leads to equivalent results as obtained with aniline.

Polysialylation of rFIX Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

12.3 mg rFIX was dissolved in 6.1 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). 254 μl of an aqueous sodium periodate solution (5 mM) was then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 6.5 μl of a 1 M aqueous cysteine solution. The mixture was subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (8.8 ml), containing oxidized rFIX was mixed with 2.46 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PSA reagent with a MW of 20 kD (described above) was added to give a 5-fold molar reagent excess. This mixture was incubated for 2.5 h at RT in the dark under gentle stirring.

The free rFIX was removed by means of anion exchange chromatography (AEC). The reaction mixture was diluted with 15 ml Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) and loaded onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. The column was then eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl 2 ), pH 7.5). Free rFIX elutes at a conductivity between 12-25 mS/cm and the conjugate between 27-45 mS/cm. The conductivity of the conjugate containing fractions was subsequently raised to 190 mS/cm with Buffer C (50 mM Hepes, 5M NaCl, 5 mM CaCl 2 ), pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl 2 ), pH 6.9). Free aminooxy-PSA reagent was washed out within 5 CV Buffer D. Subsequently the conjugate is eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl 2 ), pH 7.4). The conjugate containing fractions were concentrated by UF/DF using Vivaspin 15R 10 kD centrifugal filtrator. The final diafiltration step was performed against histidine buffer, pH 7.2 containing 150 mM NaCl and 5 mM CaCl2. The preparation was analytically characterized by measuring total protein (Bradford) and FIX chromogenic activity. The PSA-rFIX conjugate showed a specific activity of >50% in comparison to native rFIX is determined.

Method 2:

12.3 mg rFIX is dissolved in in L-histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )) to get a final protein concentration of 1 mg rFIX/ml. A 5 mM aqueous sodium periodate solution is added to get a final concentration of 100 μM and the reaction mixture is incubated for 1 hour in the dark at 4° C. under gentle stirring at pH 6.0 and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution (or other quenching reagents) to get a final concentration of 10 mM. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The obtained retentate (8.8 ml), containing oxidized rFIX, is mixed with an aqueous m-toluidine solution (50 mM) to give a final concentration of 10 mM and incubated for 30 min at room temperature. Then aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture was incubated at pH 6.0 for 2.5 hours at room temperature; 0.5 hours to 18 hours at +4° C.) in the dark under gentle stirring.

The free rFIX is removed by means of anion exchange chromatography (AEC). The reaction mixture is diluted with appropriate amounts of Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) to correct the solutions conductivity and pH prior to load onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl 2 ), pH 7.5). Free rFIX is eluted by a step gradient using 25% of Buffer B, which results in a conductivity between 12-25 mS/cm in the obtained fraction and the conjugate using a step gradient of 50% Buffer B, which results in a conductivity between 27-45 mS/cm in the conjugate fraction. The conductivity of the conjugate containing fraction is subsequently raised to 190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, 5 mM CaCl 2 ), pH 6.9 or by use of anti-chaotropic salts e.g. ammonium sulphate, ammonium acetate etc.) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn. or comparable HIC media) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl2, pH 6.9). Free aminooxy-PSA reagent is washed out within 5 CV Buffer D. Subsequently, the conjugate is eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl 2 ), pH 7.4). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against L-histidine buffer, pH 7.2 containing 150 mM NaCl and 5 mM CaCl2. The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and FIX chromogenic- and clotting activity. For the PSA-rFIX conjugate a specific activity of >50% in comparison to native rFIX is determined.

Method 3:

25.4 mg rFIX was dissolved in 18.7 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). 531 μl of an aqueous sodium periodate solution (5 mM) and 5.07 ml of an aqueous m-toluidine solution (50 mM) were then added. Subsequently, the aminooxy-PSA reagent with a MW of 20 kD (described above) was added to give a 5-fold molar reagent excess. The mixture was incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 25 μl of 1 M aqueous cysteine solution.

The free rFIX was removed by means of anion exchange chromatography (AEC). The reaction mixture was diluted with 20 ml Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) and loaded onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column was eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl 2 ), pH 7.5). Free rFIX eluted at a conductivity between 12-25 mS/cm and the conjugate between 27-45 mS/cm. The conductivity of the conjugate containing fractions was subsequently raised to 190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, 5 mM CaCl 2 ), pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl 2 ), pH 6.9). Free aminooxy-PSA reagent was washed out within 5 CV Buffer D. Subsequently, the conjugate was eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl 2 ), pH 7.4). The conjugate containing fractions were concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step was performed against histidine buffer, pH 7.2 containing 150 mM NaCl and 5 mM CaCl 2 ). The preparation was analytically characterized by measuring total protein (Bradford) and FIX chromogenic activity. For the PSA-rFIX conjugate a specific activity of >50% in comparison to native rFIX was determined. The conjugate was additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It was shown that the preparation contains no free FIX. The conjugate consisted of 57% mono-polysialylated and 31% di-polysialylated and 12% tri-polysialyated product.

Method 4:

25.4 mg rFIX was dissolved in L-histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )) to get a final protein concentration of 2 mg rFIX/ml. Subsequently an 5 mM aqueous sodium periodate solution was added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PSA reagent with a MW of 20 kD (described above) was added to give a 5-fold molar reagent excess. After correction of the pH to 6.0 the mixture was incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The free rFIX was removed by means of ion exchange chromatography (IEC). The reaction mixture was diluted with appropriate amounts of Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) to correct the solutions conductivity and pH value prior to load onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column was eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl2, pH 7.5). Free rFIX was eluted by a step gradient using 25% of Buffer B, which results in a conductivity between 12-25 mS/cm in the obtained fraction and the conjugate using a step gradient of 50% Buffer B, which results in a conductivity between 27-45 mS/cm in the conjugate fraction. The conductivity of the conjugate containing fraction was subsequently raised to 190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, 5 mM CaCl 2 ), pH 6.9; by use of anti-chaotropic salts e.g. ammonium acetate) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.; or comparable HIC media) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl2, pH 6.9). Free aminooxy-PSA reagent was washed out within 5 CV Buffer D. Subsequently the conjugate was eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl2, pH 7.4). The conjugate containing fractions were concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step was performed against L-histidine buffer, pH 7.2 containing 150 mM NaCl and 5 mM CaCl2. The preparation was analytically characterized by measuring total protein (Bradford and BCA procedure) and FIX chromogenic- and clotting activity. For the PSA-rFIX conjugate a specific activity of >50% in comparison to native rFIX was determined. The conjugate was additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It was shown that the preparation contains no free FIX. The conjugate consisted of 57% mono-polysialylated and 31% di-polysialylated and 12% tri-polysialyated product.

Polysialylation of rFVIII Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

50 mg rFVIII was transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 was added to give a final concentration of 200 μM. The oxidation was carried at RT for 30 min in the dark under gentle shaking. Then the reaction was quenched with cysteine (final concentration: 10 mM) for 60 min at RT. The solution was subjected to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which was equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column was equilibrated with 5 CV Buffer A. Then the oxidized rFVIII was eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The rFVIII containing fractions were collected. The protein content was determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl. Then a 50-fold molar excess of a aminooxy-PSA reagent with a MW of 20 kD (described above) was added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction was performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy-PSA reagent was removed by means of HIC. The conductivity of the reaction mixture was raised to 130 mS/cm by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate was eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA-rFVIII containing fractions were collected and subjected to UF/DF by use of a 30 kD membrane made of regenerated cellulose (88 cm 2 , Millipore). The preparation was analytically characterized by measuring total protein (Coomassie, Bradford) and FVIII chromogenic activity. The PSA-rFVIII conjugate showed a specific activity of >70% in comparison to native rFVIII was determined.

Method 2:

58 mg of recombinant factor VIII (rFVIII) derived from the ADVATE process in Hepes buffer (50 mM HEPES, ˜350 mM sodium chloride, 5 mM calcium chloride, 0.1% Polysorbate 80, pH 7.4) is dissolved in reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized rFVIII is further purified by anion exchange chromatography on EMD TMAE (M) (Merck). The mixture is diluted with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 6.5) to give a conductivity of 5 ms/cm. This solution is loaded onto the IEX column (bed height: 5.4 cm) with a column volume of 10 ml using a flow rate of 1.5 cm/min. This column is subsequently washed (flow rate: 1.5 cm/min) with 5 CV of a 92:8 mixture (w/w) of Buffer A and Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1.0 M NaCl, pH 7.0). Then the oxidized rFVIII is eluted with a 50:50 (w/w) mixture of Buffer A and Buffer B followed by a postelution step with 5 CV of Buffer B. The elution steps are carried out by use of a flow rate of 1.0 cm/min.

Subsequently, the aminooxy-polysialic acid (PSA-ONH 2 ) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized rFVIII within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PSA-rFVIII conjugate is purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture is spiked with ammonium acetate by addition of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture are mixed with 1 volume of the ammonium acetate containing buffer system and the pH value is corrected to pH 6.9 by drop wise addition of a 0.5 N aqueous NaOH solution. This mixture is loaded onto the HIC column at flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step is performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified PSA-rFVIII conjugate is performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of 1 cm/min. The elution of the PSA-rFVIII conjugate is monitored at UV 280 nm and the eluate containing the conjugate is collected within <4 CV. The post elution step is performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFVIII from the main product.

Finally the purified conjugate is concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with a molecular weight cut off 30 kD (88 cm 2 , Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein, FVIII chromogenic activity and determination of the polysialyation degree by measuring the PSA content (resorcinol assay). For the conjugate obtained a specific activity >50% and a PSA degree >5.0 is calculated.

Method 3:

50 mg rFVIII was transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) was added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM) and NaIO4 (final concentration: 400 μM). The coupling reaction was performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction was quenched with cysteine for 60 min at RT (final concentration: 10 mM). Then the conductivity of the reaction mixture was raised to 130 mS/cm by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently, the conjugate was eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA-rFVIII containing fractions were collected and subjected to UF/DF by use of a 30 kD membrane made of regenerated cellulose (88 cm 2 , Millipore). The preparation was analytically characterized by measuring total protein (Bradford) and FVIII chromogenic activity. For the PSA-rFVIII conjugate a specific activity of ≥70% in comparison to native rFVIII was determined.

Method 4:

50 mg recombinant factor VIII (rFVIII) derived from the ADVATE process in 50 mM Hepes buffer (50 mM HEPES, ˜350 mM sodium chloride, 5 mM calcium chloride, 0.1% Polysorbate 80, pH 7.4) was dissolved in reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution was corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent was added in a 50-fold molar excess to this rFVIII solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) was added within 15 minutes to get a final concentration of 10 mM. Finally, a 40 mM aqueous sodium periodate solution was added to give a concentration of 400 μM.

The reaction mixture was incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction was stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained PSA-rFVIII conjugate was purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture was spiked with ammonium acetate by addition of of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture was mixed with 1 volume of the ammonium acetate containing buffer system and the pH value was corrected to pH 6.9 by drop wise addition of an 0.5 N aqueous NaOH solution. This mixture was loaded onto the HIC column using a flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step was performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified rFVIII conjugate was performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of 1 cm/min. The elution of the PSA-rFVIII conjugate was monitored at UV 280 nm and the eluate containing the conjugate was collected within <4 CV. The post elution step was performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFVIII from the main product.

Finally, the purified conjugate was concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with a molecular weight cut off 30 kD (88 cm2, Millipore).

The conjugates prepared by use of this procedure were analytically characterized by measuring total protein, FVIII chromogenic activity and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Analytical data (mean of 6 consecutive batches): Process yield (Bradford): 58.9% Process yield (FVIII chrom.): 46.4% Specific activity: (FVIII chrom./mg protein): 4148 IU/mg Specific activity (% of starting material): 79.9% PSA degree (mol/mol): 8.1

PEGylation of r FVIII Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

rFVIII is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 14.7 mg rFVIII is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). Then 296 μl of an aqueous sodium periodate solution (5 mM) is added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture was subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (10.9 ml), containing oxidized rFVIII, is mixed with 2.94 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PEG reagent with a MW of 20 kD is added to give a 5-fold molar reagent excess. This mixture was incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-rFVIII conjugate is purified by ion-exchange chromatography on Q Sepharose FF. 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a 30 kD membrane (50 cm2, Millipore). The preparation is analytically characterized by measuring total protein (Coomassie, Bradford) and FVIII chromogenic activity. It is expected that the PEG-rFVIII conjugate will demonstrate a specific activity of >70% in comparison to native rFVIII was determined.

Method 2:

rFVIII is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). A starting weight or concentration of rFVIII is dissolved in or transferred to a reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized rFVIII is further purified by anion exchange chromatography on EMD TMAE (M) (Merck). The mixture is diluted with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 6.5) to give a conductivity of 5 ms/cm. This solution is loaded onto the IEX column (bed height: 5.4 cm) with a column volume of 10 ml using a flow rate of 1.5 cm/min. This column is subsequently washed (flow rate: 1.5 cm/min) with 5 CV of a 92:8 mixture (w/w) of Buffer A and Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1.0 M NaCl, pH 7.0). Then the oxidized rFVIII is eluted with a 50:50 (w/w) mixture of Buffer A and Buffer B followed by a postelution step with 5 CV of Buffer B. The elution steps are carried out by use of a flow rate of 1.0 cm/min.

Subsequently, the aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized rFVIII within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-rFVIII conjugate is purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture is spiked with ammonium acetate by addition of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture are mixed with 1 volume of the ammonium acetate containing buffer system and the pH value is corrected to pH 6.9 by drop wise addition of a 0.5 N aqueous NaOH solution. This mixture is loaded onto the HIC column using a flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step is performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified rFVIII conjugate is performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of lcm/min. The elution of the PEG-rFVIII conjugate is monitored at UV 280 nm and the eluate containing the conjugate is collected within <4 CV. The post elution step is performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFVIII from the main product.

Finally, the purified conjugate is concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with a molecular weight cut off 30 kD (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

rFVIII is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 7.84 mg rFVIII, dissolved in 6 ml Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) are mixed with 314 μl of an aqueous sodium periodate solution (10 mM), and 1.57 ml of an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally the PEG-rFVIII conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a 30 kD membrane (88 cm 2 , Millipore). The analytical characterization of the conjugate by FVIII chromogenic assay and determination of total protein (Bradford) shows a specific activity of >60% compared to the rFVIII starting material.

Method 4:

rFVIII is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of rFVIII is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg rFVIII/ml. Subsequently, an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The free rFVIII is removed by means of ion exchange chromatography (IEC). The reaction mixture was diluted with appropriate amounts of Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) to correct the solutions conductivity and pH value prior to load onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column was eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl2, pH 7.5). Free rFVIII was eluted by a step gradient using 25% of Buffer B, which results in a conductivity between 12-25 mS/cm in the obtained fraction and the conjugate using a step gradient of 50% Buffer B, which results in a conductivity between 27-45 mS/cm in the conjugate fraction. The conductivity of the conjugate containing fraction is subsequently raised with Buffer C (50 mM Hepes, 5 M NaCl, 5 mM CaCl 2 ), pH 6.9; by use of anti-chaotropic salts e.g. ammonium acetate, ammonium sulphate etc.) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.; or comparable HIC media) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl 2 ), pH 6.9). Free PEG-reagent was washed out within 5 CV Buffer D. Subsequently, the conjugate was eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl2, pH 7.4). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

Polysialylation of rFVIIa Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration or weight of recombinant factor VIIa (rFVIIa) is transferred or dissolved in reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous NaOH solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 50 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized rFVIIa is further purified by anion exchange chromatography on EMD TMAE (M) (Merck). The mixture is diluted with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 6.5) to give a conductivity of 5 ms/cm. This solution is loaded onto the IEX column (bed height: 5.4 cm) with a column volume of 10 ml using a flow rate of 1.5 cm/min. This column is subsequently washed (flow rate: 1.5 cm/min) with 5 CV of a 92:8 mixture (w/w) of Buffer A and Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1.0 M NaCl, pH 7.0). Then the oxidized rFVIIa is eluted with a 50:50 (w/w) mixture of Buffer A and Buffer B followed by a postelution step with 5 CV of Buffer B. The elution steps are carried out by use of a flow rate of 1.0 cm/min.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized rFVIIa within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PSA-rFVIIa conjugate is purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture is spiked with ammonium acetate by addition of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture are mixed with 1 volume of the ammonium acetate containing buffer system and the pH value is corrected to pH 6.9 by drop wise addition of a 0.5 N aqueous NaOH solution. This mixture is loaded onto the HIC column using a flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step is performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified rFVIIa conjugate is performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of 1 cm/min. The elution of the PSA-rFVIIa conjugate is monitored at UV 280 nm and the eluate containing the conjugate is collected within <4 CV. The post elution step is performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFVIIa from the main product.

Finally, the purified conjugate is concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (e.g. 10 kD MWCO, 88 cm 2 , Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 2:

A starting weight or concentration of rFVIIa is dissolved in or transferred to a reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous NaOH solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this rFVIIa solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 150 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained PSA-rFVIIa conjugate is purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture is spiked with ammonium acetate by addition of of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture is mixed with 1 volume of the ammonium acetate containing buffer system and the pH value is corrected to pH 6.9 by drop wise addition of an 0.5 N aqueous NaOH solution. This mixture is loaded onto the HIC column using a flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step is performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified rFVIIa conjugate is performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of 1 cm/min. The elution of the PSA-rFVIIa conjugate is monitored at UV 280 nm and the eluate containing the conjugate was collected within <4 CV. The post elution step is performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFVIII from the main product.

Finally, the purified conjugate is concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

PEGylation of rFIX Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

rFIX is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). A starting weight or concentration of rFIX is dissolved in or transferred to a reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized rFVIII is further purified by anion exchange chromatography on EMD TMAE (M) (Merck). The mixture is diluted with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 6.5) to give a conductivity of 5 mS/cm. This solution is loaded onto the IEX column (bed height: 5.4 cm) with a column volume of 10 ml using a flow rate of 1.5 cm/min. This column is subsequently washed (flow rate: 1.5 cm/min) with 5 CV of a 92:8 mixture (w/w) of Buffer A and Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1.0 M NaCl, pH 7.0). Then the oxidized rFIX is eluted with a 50:50 (w/w) mixture of Buffer A and Buffer B followed by a postelution step with 5 CV of Buffer B. The elution steps are carried out by use of a flow rate of 1.0 cm/min.

Subsequently, the aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized rFIX within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-rFIX conjugate is purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture is spiked with ammonium acetate by addition of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture are mixed with 1 volume of the ammonium acetate containing buffer system and the pH value is corrected to pH 6.9 by drop wise addition of a 0.5 N aqueous NaOH solution. This mixture is loaded onto the HIC column using a flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step is performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified rFIX conjugate is performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of 1 cm/min. The elution of the PEG-rFIX conjugate is monitored at UV 280 nm and the eluate containing the conjugate is collected within <4 CV. The post elution step is performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFIX from the main product.

Finally, the purified conjugate is concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with a molecular weight cut off 10 kD (88 cm2, Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 2:

rFIX is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of rFIX is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg rFIX/ml. Subsequently, an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The free rFIX is removed by means of ion exchange chromatography (IEC). The reaction mixture was diluted with appropriate amounts of Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) to correct the solutions conductivity and pH value prior to load onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column was eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl2, pH 7.5). Free rFIX was eluted by a step gradient using 25% of Buffer B, which results in a conductivity between 12-25 mS/cm in the obtained fraction and the conjugate using a step gradient of 50% Buffer B, which results in a conductivity between 27-45 mS/cm in the conjugate fraction. The conductivity of the conjugate containing fraction is subsequently raised with Buffer C (50 mM Hepes, 5 M NaCl, 5 mM CaCl 2 ), pH 6.9; by use of anti-chaotropic salts e.g. ammonium acetate, etc) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.; or comparable HIC media) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl2, pH 6.9). Free aminooxy-PEG reagent was washed out within 5 CV Buffer D. Subsequently, the conjugate was eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl 2 ), pH 7.4). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of rFVIIa Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

rFVIIa is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). A starting weight or concentration of rFVIIa is dissolved in or transferred to a reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous NaOH solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 50 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized rFVIIa is further purified by anion exchange chromatography on EMD TMAE (M) (Merck). The mixture is diluted with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 6.5) to give a conductivity of 5 mS/cm. This solution is loaded onto the IEX column (bed height: 5.4 cm) with a column volume of 10 ml using a flow rate of 1.5 cm/min. This column is subsequently washed (flow rate: 1.5 cm/min) with 5 CV of a 92:8 mixture (w/w) of Buffer A and Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1.0 M NaCl, pH 7.0). Then the oxidized rFVIIa is eluted with a 50:50 (w/w) mixture of Buffer A and Buffer B followed by a postelution step with 5 CV of Buffer B. The elution steps are carried out by use of a flow rate of 1.0 cm/min.

Subsequently, the aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized rFVIIa within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-rFVIIa conjugate is purified by Hydrophobic Interaction Chromatography (HIC) using a Phenyl Sepharose FF low sub resin (GE Healthcare) packed into a column manufactured by GE Healthcare with a bed height (h) of 15 cm and a resulting column volume (CV) of 81 ml.

The reaction mixture is spiked with ammonium acetate by addition of 50 mM Hepes buffer, containing 350 mM sodium chloride, 8 M ammonium acetate, 5 mM calcium chloride, pH 6.9. Two volumes of the reaction mixture are mixed with 1 volume of the ammonium acetate containing buffer system and the pH value is corrected to pH 6.9 by drop wise addition of a 0.5 N aqueous NaOH solution. This mixture is loaded onto the HIC column using a flow rate of 1 cm/min followed by a washing step using >3 CV equilibration buffer (50 mM Hepes, 350 mM sodium chloride, 2.5 M ammonium acetate, 5 mM calcium chloride, pH 6.9).

For removal of reaction by-products and anti-chaotropic salt a second washing step is performed with >5 CV washing buffer 1 (50 mM Hepes, 3 M sodium chloride, 5 mM calcium chloride, pH 6.9) in upflow mode at a flow rate of 2 cm/min. Then elution of purified rFVIIa conjugate is performed in down flow mode using a step gradient of 40% washing buffer 2 (50 mM Hepes, 1.5 M sodium chloride, 5 mM calcium chloride, pH 6.9) and 60% elution buffer (20 mM Hepes, 5 mM calcium chloride, pH 7.5) at a flow rate of 1 cm/min. The elution of the PEG-rFVIIa conjugate is monitored at UV 280 nm and the eluate containing the conjugate is collected within <4 CV. The post elution step is performed with >3 CV elution buffer under the same conditions to separate minor and/or non modified rFVIIa from the main product.

Finally, the purified conjugate is concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with a molecular weight cut off 10 kD (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 2:

rFVIIa is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of rFVIIa is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg rFVIIa/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The free rFVIIa is removed by means of ion exchange chromatography (IEC). The reaction mixture was diluted with appropriate amounts of Buffer A (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5) to correct the solutions conductivity and pH value prior to load onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column was eluted with Buffer B (50 mM Hepes, 1 M NaCl, 5 mM CaCl2, pH 7.5). Free rFVIIa was eluted by a step gradient using 25% of Buffer B, which results in a conductivity between 12-25 mS/cm in the obtained fraction and the conjugate using a step gradient of 50% Buffer B, which results in a conductivity between 27-45 mS/cm in the conjugate fraction. The conductivity of the conjugate containing fraction is subsequently raised with Buffer C (50 mM Hepes, 5 M NaCl, 5 mM CaCl 2 ), pH 6.9; by use of anti-chaotropic salts e.g. ammonium acetate) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.; or comparable HIC media) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, 5 mM CaCl 2 ), pH 6.9). Free PEG-reagent was washed out within 5 CV Buffer D. Subsequently the conjugate was eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl 2 ), pH 7.4). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

Polysialylation of rFIX in the Presence of o-Amino Benzoic Acid

Method 1:

8.2 mg rFIX is dissolved in 4.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). Then 82 μl of an aqueous sodium periodate solution (5 mM) is added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 4 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 6 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (6.5 ml), containing oxidized rFIX, is mixed with 1.64 ml of an aqueous o-amino benzoic acid (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture was incubated for 2.5 h at room temperature in the dark under gentle stirring.

The further purification of the conjugate is carried out as described herein.

Method 2:

A solution of 1 mg rFIX in 0.65 ml sodium phosphate buffer, pH 6.0 containing a 5-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) was prepared. Then 333 μl of an aqueous o-amino benzoic acid solution (30 mM) was added as nucleophilic catalyst to give a final concentration of 10 mM. Subsequently 20 μl of an aqueous solution of NaIO4 (5 mM) was added yielding in a final concentration of 100 μM. The coupling process was performed for 2 hours in the dark under gentle shaking at room temperature and quenched for 15 min at room temperature by the addition of 1 μl of aqueous cysteine solution (1 M). The further purification of the conjugate is carried out as described herein.

Polysialylation of EPO Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of erythropoietin (EPO) is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized EPO is eluted with Buffer B (20 mM Hepes, 5 mM CaCl2, 1M NaCl, pH 7.0). The EPO containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5M HCl.

A 50-fold molar excess of a aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy-PSA reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally the PSA-EPO containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (MWCO 10 kD, 50 cm 2 , Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows.

10 mg EPO is dissolved in 5 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 100 μl of an aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 50 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (approx. 7 ml), containing oxidized EPO, is mixed with 2 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at RT in the dark under gentle stirring.

The free EPO is removed by means of anion exchange chromatography (AEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 7.5) and loaded onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 7.5). Free EPO is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently, the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 7.4). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 7.2 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA-EPO conjugate a specific activity of >50% in comparison to native EPO is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free EPO.

Method 2:

EPO is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized EPO is further purified by ion exchange chromatography. The oxidized EPO containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized EPO within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-EPO conjugate is further purified by ion exchange chromatography. The PSA-EPO conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Erythropoietin (EPO) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50 fold molar excess of a aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA-EPO containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (MWCO 10 kD, 88 cm2, Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. 10 mg EPO is dissolved in 8 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently, the aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

The free EPO is removed by means of anion exchange chromatography (AEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 7.5) and loaded onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 7.5). Free EPO is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently, the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 7.4). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against histidine buffer, pH 7.2 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA-EPO conjugate a specific activity of >50% in comparison to native EPO is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free EPO.

Method 4:

EPO is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this EPO solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained PSA-EPO conjugate is purified by ion-exchange chromatography. The PSA-EPO containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (MWCO 10 kD, 88 cm2, Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Ang-2 Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of angiopoietin-2 (Ang-2) is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts, or, in the alternative, subjected to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized Ang-2 is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1 M NaCl, pH 7.0). The Ang-2 containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA—Ang-2-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Angiopoietin-2 (Ang-2) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at R.T.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-Ang-2 conjugate-containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

Ang-2 is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized Ang-2 is further purified by ion exchange chromatography. The oxidized Ang-2 containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized Ang-2 within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-Ang-2 conjugate is further purified by ion-exchange chromatography

The PSA-Ang-2 conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Angiopoietin-2 (Ang-2) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50 fold molar excess of a PSA aminooxy reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA Ang-2-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Angiopoietin-2 (Ang-2) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of a PSA aminooxy reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. PSA Ang-2-containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

Ang-2 is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this Ang-2 solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained PSA-Ang-2 conjugate is purified by ion-exchange chromatography. The PSA-Ang-2 containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of VEGF Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of vascular endothelial growth factor (VEGF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized VEGF is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1 M NaCl, pH 7.0). The VEGF containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5M NaOH.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally the PSA—VEGF-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Vascular endothelial growth factor (VEGF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA—VEGF-containing fractions of the eluate are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

VEGF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized VEGF is further purified by ion exchange chromatography. The oxidized VEGF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized VEGF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-VEGF conjugate is further purified by ion exchange chromatography. The PSA-VEGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Vascular endothelial growth factor (VEGF) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of a PSA aminooxy reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA-VEGF containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Vascular endothelial growth factor (VEGF) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. The PSA-VEGF containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

VEGF is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this VEGF solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained VEGF-conjugate is purified by ion-exchange chromatography. The PSA-VEGF containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of EGF Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of epidermal growth factor (EGF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at R.T.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized EGF is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The EGF containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA-EGF containing fractions are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Epidermal growth factor (EGF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at R.T.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-EGF containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

EGF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized EGF is further purified by ion exchange chromatography. The oxidized EGF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized EGF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-EGF conjugate is further purified by ion exchange chromatography. The PSA-EGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Epidermal growth factor (EGF) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of a PSA aminooxy reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally the PSA-EGF containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Epidermal growth factor (EGF) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of a PSA aminooxy reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. The conjugate containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

EGF is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this EGF-solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained EGF-conjugate is purified by ion-exchange chromatography. The PSA-EGF containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of NGF Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of nerve growth factor (NGF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized NGF is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The NGF containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA-NGF containing fractions are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Nerve growth factor (NGF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-NGF containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

NGF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized NGF is further purified by ion exchange chromatography. The oxidized NGF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized NGF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-NGF conjugate is further purified by ion exchange chromatography. The PSA-NGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Nerve growth factor (NGF) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA NGF-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Nerve growth factor (NGF) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. Then the PSA-NGF containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

NGF is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this NGF-solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained NGF-conjugate is purified by ion-exchange chromatography. The PSA-NGF containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of HGH Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

A starting concentration of human growth hormone (HGH) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized HGH is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1 M NaCl, pH 7.0). The HGH containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA-HGH containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art. HGH is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-HGH containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized HGH is further purified by ion exchange chromatography. The oxidized HGH containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized HGH within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-HGH conjugate is further purified by ion exchange chromatography. The PSA-HGH conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

Human growth hormone (HGH) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50 fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA HGH-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art. HGH is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50 fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. Then the PSA-HGH-containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this HGH-solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained HGH-conjugate is purified by ion-exchange chromatography. The PSA-HGH containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of TNF-Alpha Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

A starting concentration of tumor necrosis factor-alpha (TNF-alpha) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized TNF-alpha is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The TNF-alpha containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally the PSA-TNF-alpha-containing fractions are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Tumor necrosis factor-alpha (TNF-alpha) is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-TNF-alpha containing fractions of the eluate are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

TNF-alpha is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized TNF-alpha is further purified by ion exchange chromatography. The oxidized TNF-alpha containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized TNF-alpha within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-TNF-alpha conjugate is further purified by ion exchange chromatography. The PSA-TNF-alpha conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Tumor necrosis factor-alpha (TNF-alpha) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally the PSA-TNF-alpha-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Tumor necrosis factor-alpha (TNF-alpha) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM).and the conjugate is purified by ion exchange chromatography. The PSA-TNF-alpha containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

TNF-alpha is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this TNF-alpha-solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained TNF-alpha conjugate is purified by ion-exchange chromatography. The PSA-TNF-alpha containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Insulin Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art. A starting concentration of insulin is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized insulin is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1 M NaCl, pH 7.0). The insulin containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally the PSA-insulin containing fractions are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art. Insulin is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-insulin containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized insulin is further purified by ion exchange chromatography. The oxidized insulin containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized insulin within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-insulin conjugate is further purified by ion exchange chromatography. The PSA-insulin conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA-insulin containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. PSA-insulin containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this insulin-solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained insulin conjugate is purified by ion-exchange chromatography. The PSA-insulin containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Interferon-Alpha Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of interferon-alpha is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized interferon-alpha is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The interferon-alpha containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally the PSA-interferon-alpha containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Interferon-alpha is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion-exchange chromatography. The PSA-interferon-alpha containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

Interferon-alpha is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized interferon-alpha is further purified by ion exchange chromatography. The oxidized interferon-alpha containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized interferon-gamma within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-interferon-alpha conjugate is further purified by ion exchange chromatography. The PSA-interferon-alpha conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

Method 3:

Interferon-alpha is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of a PSA aminooxy reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA-interferon-alpha containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Interferon-alpha is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. The PSA-interferon-alpha containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

Interferon-alpha is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this interferon-alpha solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally, a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained interferon-alpha conjugate is purified by ion-exchange chromatography. The PSA-interferon-alpha containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Interferon-Gamma Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

10 mg interferon-gamma is dissolved in 5 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 100 μl of an aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 50 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (approx. 7 ml), containing oxidized interferon-gamma, is mixed with 2 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at RT in the dark under gentle stirring.

The free Interferon-gamma is removed by means of cation exchange chromatography (CEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free interferon-gamma is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently, the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 6.9). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA-Interferon-gamma conjugate a specific activity of >50% in comparison to native Interferon-gamma is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free Interferon gamma.

Method 2:

10 mg interferon-gamma is dissolved in 8 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently the aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

The free interferon gamma is removed by means of cation exchange chromatography (CEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free interferon-gamma is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently, the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 6.9). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA interferon-gamma conjugate a specific activity of >50% in comparison to native interferon-gamma is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free interferon-gamma.

Method 3:

10 mg interferon-gamma is dissolved in 8 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently the aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

The free interferon gamma is removed by means of cation exchange chromatography (CEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free interferon-gamma is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 6.9). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA interferon-gamma conjugate a specific activity of >50% in comparison to native interferon-gamma is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free interferon-gamma.

Method 4:

Interferon-gamma is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this interferon-gamma solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally, a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained interferon-gamma conjugate is purified by ion-exchange chromatography. The PSA-interferon-gamma containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of G-CSF Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of granulocyte-colony stimulating factor (G-CSF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized G-CSF is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1 M NaCl, pH 7.0). The G-CSF containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently, the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally the PSA-G-CSF-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Granulocyte-colony stimulating factor (G-CSF) is transferred into a reaction buffer (e.g., 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mm). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography. The PSA-G-CSF containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

G-CSF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized G-CSF is further purified by ion exchange chromatography. The oxidized G-CSF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized G-CSF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-G-CSF conjugate is further purified by ion exchange chromatography. The PSA-G-CSF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Granulocyte-colony stimulating factor (G-CSF) is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally, the PSA-G-CSF-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Granulocyte-colony stimulating factor (G-CSF) is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. The PSA-G-CSF containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

G-CSF is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this G-CSF solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally, a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained G-CSF conjugate is purified by ion-exchange chromatography. The PSA-G-CSF containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Humira Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of Humira is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized Humira is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The Humira containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA-Humira containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Humira is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mm). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of ion exchange chromatography The PSA-Humira containing fractions of the eluate are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

Humira is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized Humira is further purified by ion exchange chromatography. The oxidized Humira containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized Humira within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained PSA-Humira conjugate is further purified by ion exchange chromatography. The PSA-Humira conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Humira is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally the PSA-Humira containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Humira is transferred into reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM) and the conjugate is purified by ion exchange chromatography. The PSA-Humira containing fractions of the eluate are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

Humira is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently, the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this Humira solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained Humira-conjugate is purified by ion-exchange chromatography. The PSA-Humira containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Prolia Using Aminooxy-PSA and m-Toluidine as a Nucleophilic Catalyst

Method 1:

A starting concentration of Prolia is transferred into a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. To this solution, NaIO4 is added to give a final concentration of 200 μM. The oxidation is carried at RT for 30 min in the dark under gentle shaking. The reaction is then quenched with cysteine (final concentration: 10 mM) for 60 min at RT.

The solution is next subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof or, in the alternative, to an IEX column with a volume of 20 ml (Merck EMD TMAE (M)) which is equilibrated with Buffer A (20 mM Hepes, 5 mM CaCl 2 ), pH 7.0). The column is equilibrated with 5 CV Buffer A. The oxidized Prolia is eluted with Buffer B (20 mM Hepes, 5 mM CaCl 2 ), 1M NaCl, pH 7.0). The Prolia containing fractions are collected. The protein content is determined (Coomassie, Bradford) and adjusted to 1 mg/ml with reaction buffer and adjusted to pH 6.0 by dropwise addition of 0.5 M HCl.

A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (final concentration: 10 mM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. The excess of aminooxy reagent is removed by means of HIC. The conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with 80 ml Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes buffer pH 7.5 containing 5 mM CaCl 2 ). Finally, the PSA-Prolia containing fractions are collected and subjected to UF/DF by use of a a membrane made of regenerated cellulose (Millipore). The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. 10 mg Prolia is dissolved in 5 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 100 μl of an aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 50 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (approx. 7 ml), containing oxidized Prolia, is mixed with 2 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at RT in the dark under gentle stirring.

The free Prolia is removed by means of cation exchange chromatography (CEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free Prolia is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently, the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 6.9). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD, Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA-Prolia conjugate a specific activity of >50% in comparison to native Prolia is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free Prolia.

Method 2:

Prolia is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized Prolia is further purified by ion exchange chromatography. The oxidized Prolia containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized Prolia within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. at pH 6.0 in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking (protein concentration: 1 mg/ml).

The obtained Prolia conjugate is further purified by ion exchange chromatography. The Prolia conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure is analytically characterized by measuring total protein, biological activity, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Method 3:

Prolia is transferred into reaction buffer (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and diluted to obtain a protein concentration of 1 mg/ml. A 50-fold molar excess of aminooxy-PSA reagent with a MW of 20 kD (described above) is added followed by m-toluidine as a nucleophilic catalyst (10 mM final concentration) and NaIO4 (final concentration: 400 μM). The coupling reaction is performed for 2 hours in the dark under gentle shaking at room temperature. Subsequently, the reaction is quenched with cysteine for 60 min at RT (cysteine concentration: 10 mM). Then the conductivity of the reaction mixture is adjusted by adding a buffer containing ammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, 8 M ammonium acetate, pH 6.9) and loaded onto a column filled with Phenyl Sepharose FF (GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calcium chloride, pH 7.5. Finally the PSA Prolia-containing fractions are collected and subjected to UF/DF by use of a membrane made of regenerated cellulose (Millipore). The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. 10 mg Prolia is dissolved in 8 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently the aminooxy-PSA reagent with a MW of 20 kD (described above) is added to give a 5 fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

The free Prolia is removed by means of cation exchange chromatography (CEC). The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free Prolia is eluted by washing the column with 25% Buffer B and the conjugate at 5 0% Buffer B. The conductivity of the conjugate containing fractions is subsequently raised to ˜190 mS/cm with Buffer C (50 mM Hepes, 5 M NaCl, pH 6.9) and loaded onto a 20 ml HiPrep Butyl FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer D (50 mM Hepes, 3 M NaCl, pH 6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequently the conjugate is eluted with 100% Buffer E (50 mM Hepes, pH 6.9). The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm 2 , cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PSA-Prolia conjugate a specific activity of >50% in comparison to native Prolia is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free Prolia.

Method 4:

Prolia_is dissolved in or transferred to a reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution.

Subsequently the aminooxy-polysialic acid (PSA-ONH2) reagent is added in a 50-fold molar excess to this Prolia—solution within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. Finally a 40 mM aqueous sodium periodate solution is added to give a concentration of 400 μM.

The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking. Then the reaction is stopped by the addition of an aqueous L-cysteine solution (1 M) to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The obtained Prolia conjugate is purified by ion-exchange chromatography. The PSA-Prolia containing fractions of the eluate are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose (Millipore).

The conjugates prepared by use of this procedure are analytically characterized by measuring total protein, biological activity according to methods known in the art, and determination of the polysialyation degree by measuring the PSA content (resorcinol assay).

Polysialylation of Other Therapeutic Proteins

Polysialylation reactions performed in the presence of alternative nucleophilic catalysts like m-toluidine or o-aminobenzoic acid as described herein may be extended to other therapeutic proteins. For example, in various aspects of the invention, the above polysialylation or PEGylation reactions as described herein with PSA aminooxy or PEG aminooxy reagents is repeated with therapeutic proteins such as those proteins described herein.

PEGylation of EPO Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

Erythropoietin (EPO) is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EPO is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized EPO is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-EPO conjugate is purified by ion-exchange chromatography (e.g. on Q Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. EPO is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 10 mg EPO is dissolved in 5 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 100 μl of an aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 50 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (approx. 7 ml), containing oxidized EPO, is mixed with 2 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at RT in the dark under gentle stirring.

Finally, the PEG-EPO conjugate is purified by ion-exchange chromatography on Q Sepharose FF. The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 7.5) and loaded onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 7.5). Free EPO is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 7.2 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity biological activity according to methods known in the art.. For the PEG-EPO conjugate a specific activity of >50% in comparison to native EPO is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free EPO.

Method 2:

EPO is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan).

EPO is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized EPO is further purified by ion exchange chromatography. The oxidized EPO containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized EPO within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-EPO conjugate is further purified by ion exchange chromatography. The PEG-EPO conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

EPO is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EPO is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-EPO conjugate is purified by ion-exchange chromatography on Q Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. EPO is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 10 mg EPO is dissolved in ˜8 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently, the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

Finally, the PEG-EPO conjugate is purified by ion-exchange chromatography on Q Sepharose FF. The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 7.5) and loaded onto a 20 ml HiPrep QFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 7.5). Free EPO is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 7.2 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PEG-EPO conjugate a specific activity of >50% in comparison to native EPO is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free EPO.

Method 4:

EPO is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of EPO is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg EPO/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-EPO conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm 2 , cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of Ang-2 Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

Ang-2 is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Ang-2 is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized Ang-2 is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-Ang-2 conjugate is purified by ion-exchange chromatography (e.g. on Q Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Ang-2 is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Ang-2 is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized Ang-2 is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-Ang-2 conjugate is purified by ion-exchange chromatography. The conjugate containing fraction of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

Ang-2 is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan).

Ang-2 is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized Ang-2 is further purified by ion exchange chromatography. The oxidized Ang-2 containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized Ang-2 within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-Ang-2 conjugate is further purified by ion exchange chromatography. The PEG-Ang-2 conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

Ang-2 is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Ang-2 is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-Ang-2 conjugate is purified by ion-exchange chromatography on Q Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Ang-2 is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Ang-2 is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally the PEG-Ang-2 conjugate is purified by ion-exchange chromatography The conjugate containing fractions of the eluate are collected and then subjected to UF/DF.. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

Ang-2 is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of Ang-2 is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg Ang-2/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-Ang-2 conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods..

Subsequently, the free Ang-2 is removed by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF.

PEGylation of VEGF Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

VEGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). VEGF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized VEGF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-VEGF conjugate is purified by ion-exchange chromatography (e.g., on Q Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. VEGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). VEGF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized VEGF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-VEGF conjugate is purified by ion-exchange chromatography The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

VEGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan).VEGF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized VEGF is further purified by ion exchange chromatography. The oxidized VEGF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized VEGF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-VEGF conjugate is further purified by ion exchange chromatography. The PEG-VEGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

VEGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). VEGF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-VEGF conjugate is purified by ion-exchange chromatography on Q Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. VEGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). VEGF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-VEGF conjugate is purified by ion-exchange chromatography. The conjugate fractions of the eluate are collected and then subjected to UF/DF. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

VEGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of VEGF is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg VEGF/ml. Subsequently, an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-VEGF conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of EGF Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

EGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EGF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized EGF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-EGF conjugate is purified by ion-exchange chromatography (e.g., on Q Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. EGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EGF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized EGF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-EGF conjugate is purified by ion-exchange chromatography. The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

EGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EGF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized EGF is further purified by ion exchange chromatography. The oxidized EGF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized NGF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-EGF conjugate is further purified by ion exchange chromatography. The PEG-EGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

EGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EGF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-EGF conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. EGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EGF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-EGF conjugate is purified by ion-exchange chromatography. The conjugate containing fractions of the eluate are collected and then subjected to UF/DF. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

EGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of EGF is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg EGF/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-EGF conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of NGF Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

NGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). NGF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized NGF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-NGF conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. NGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). NGF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized NGF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-NGF conjugate is purified by ion-exchange chromatography (The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

NGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). NGF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized NGF is further purified by ion exchange chromatography. The oxidized NGF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized NGF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-NGF conjugate is further purified by ion exchange chromatography. The PEG-NGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

NGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). NGF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-NGF conjugate is purified by ion-exchange chromatography on Q Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. NGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). NGF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-NGF conjugate is purified by ion-exchange chromatography. The conjugate containing fractions are collected and then subjected to UF/DF. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

NGF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of NGF is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg NGF/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-NGF conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of HGH Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). HGH is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized HGH is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-HGH conjugate is purified by ion-exchange chromatography (e.g., on Q Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In n alternative embodiment, Method 1 is carried out as follows. As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). HGH is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized HGH is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-HGH conjugate is purified by ion-exchange chromatography (The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). HGH is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized HGH is further purified by ion exchange chromatography. The oxidized HGH containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized HGH within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-HGH conjugate is further purified by ion exchange chromatography. The PEG-NGF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). HGH is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-HGH conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art. HGH is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). HGH is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-HGH conjugate is purified by ion-exchange chromatography. The conjugate containing fractions are collected and then subjected to UF/DF. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

As described herein, the amino acid sequence of human growth hormone (HGH) is first modified to incorporate at least one glycosylation site. Following purification, HGH is glycosylated in vitro according to methods known in the art.

HGH is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of HGH is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg HGH/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-HGH conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of TNF-Alpha Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

TNF-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). TNF-alpha is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized TNF-alpha is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-TNF-alpha conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. TNF-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). TNF-alpha is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized TNF-alpha is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-TNF-alpha conjugate is purified by ion-exchange chromatography. The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

TNF-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). TNF-alpha is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized TNF-alpha is further purified by ion exchange chromatography. The oxidized TNF-alpha containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized TNF alpha within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-TNF-alpha conjugate is further purified by ion exchange chromatography. The PEG-TNF-alpha conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

TNF-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). TNF-alpha is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-TNF-alpha conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. TNF-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). TNF-alpha is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-TNF-alpha conjugate is purified by ion-exchange chromatography. The conjugate containing fractions are collected and then subjected to UF/DF. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

TNF-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of TNF-alpha is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg TNF-alpha/ml. Subsequently, an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-TNF-alpha conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of insulin using an aminooxy-PEG reagent and m-toluidine as a nucleophilic catalyst

Method 1:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art. Insulin is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Insulin is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized insulin is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-insulin conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art. Insulin is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Insulin is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized insulin is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-insulin conjugate is purified by ion-exchange chromatography. The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Insulin is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized insulin is further purified by ion exchange chromatography. The oxidized insulin containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized insulin within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-insulin conjugate is further purified by ion exchange chromatography. The PEG-insulin conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Insulin is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-insulin conjugate is purified by ion-exchange chromatography on Q Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art. Insulin is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Insulin is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the insulin-conjugate is purified by ion-exchange chromatography. The conjugate containing fractions are collected and then subjected to UF/DF. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

As described herein, the amino acid sequence of insulin is first modified to incorporate at least one glycosylation site. Following purification, insulin is glycosylated in vitro according to methods known in the art.

Insulin is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of insulin is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg insulin/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-insulin conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of Interferon-Alpha Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

Interferon-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Interferon-alpha is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized interferon-alpha is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-interferon-alpha conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Interferon-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Interferon-alpha is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized interferon-alpha is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-interferon-alpha conjugate is purified by ion-exchange chromatography The conjugate containing fractions are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

Interferon-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Interferon-alpha is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized interferon-alpha is further purified by ion exchange chromatography. The oxidized interferon-alpha containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized interferon-alpha within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-interferon-alpha conjugate is further purified by ion exchange chromatography. The PEG-interferon alpha conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

Interferon-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Interferon-alpha is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-interferon-alpha conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Interferon-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Interferon-alpha is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-interferon-alpha conjugate is purified by ion-exchange chromatography. The conjugate containing fractions are collected and then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

Interferon-alpha is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of interferon-alpha is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg interferon-alpha/ml. Subsequently, an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-interferon-alpha conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of Interferon-Gamma Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

Interferon-gamma is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 10 mg Interferon-gamma is dissolved in 5 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 100 μl of an aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 50 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (approx. 7 ml), containing oxidized interferon-gamma, is mixed with 2 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at RT in the dark under gentle stirring.

Finally, the PEG-interferon-gamma conjugate is purified by ion-exchange chromatography on SP Sepharose FF. The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free interferon-gamma is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PEG-interferon-gamma conjugate a specific activity of >50% in comparison to native Interferon gamma is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free Interferon-gamma.

Method 2:

Interferon-gamma is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Interferon-gamma is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5 N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized interferon-gamma is further purified by ion exchange chromatography. The oxidized interferon-gamma containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized interferon-gamma within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-interferon-gamma conjugate is further purified by ion exchange chromatography. The PEG-interferon-gamma conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

The conjugate prepared by use of this procedure are analytically characterized by measuring total protein and biological activity according to methods known in the art.

Method 3:

Interferon-gamma is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 10 mg interferon-gamma is dissolved in ˜8 ml histidine—buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

Finally the PEG-interferon-gamma conjugate is purified by ion-exchange chromatography on SP-Sepharose FF. The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SP FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free interferon-gamma is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PEG-interferon-gamma conjugate a specific activity of >50% in comparison to native interferon-gamma is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free interferon-gamma.

Method 4:

Interferon-gamma is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of interferon-gamma is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg interferon-gamma/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The PEG-interferon-gamma conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of G-CSF Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

G-CSF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). G-CSF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 m4) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized G-CSF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-G-CSF conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. G-CSF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). G-CSF is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized G-CSF is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-G-CSF conjugate is purified by ion-exchange chromatography (The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

G-CSF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). G-CSF is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized G-CSF is further purified by ion exchange chromatography. The oxidized G-CSF containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized G-CSF within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-G-CSF conjugate is further purified by ion exchange chromatography. The PEG-G-CSF conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

Method 3:

G-CSF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). G-CSF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-G-CSF conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. G-CSF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). G-CSF is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-G-CSF conjugate is purified by ion-exchange chromatography. The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

G-CSF is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of G-CSF is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg G-CSF/ml. Subsequently, an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The G-CSF conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of Humira Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

Humira is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Humira is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized Humira is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-Humira conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Humira is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Humira is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized Humira is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-Humira conjugate is purified by ion-exchange chromatography. The conjugate containing fractions of the eluate are collected and then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

Method 2:

Humira is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Humira is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized Humira is further purified by ion exchange chromatography. The oxidized Humira containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized Humira within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-Humira conjugate is further purified by ion exchange chromatography. The PEG-Humira conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

Method 3:

Humira is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Humira is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently, the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-Humira conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows. Humira is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Humira is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-Humira conjugate is purified by ion-exchange chromatography. The conjugate containing fractions are collected and then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

Method 4:

Humira is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of Humira is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg Humira/ml. Subsequently an 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of a 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The Humira conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of Prolia Using an Aminooxy-PEG Reagent and m-Toluidine as a Nucleophilic Catalyst

Method 1:

Prolia is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Prolia is dissolved in 7.0 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl, 5 mM CaCl 2 )). An aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 7.5 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate containing oxidized Prolia is next mixed with an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Aminooxy-PEG reagent with a MW of 20 kD is then added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at room temperature in the dark under gentle stirring.

Finally, the PEG-Prolia conjugate is purified by ion-exchange chromatography (e.g., on Q-Sepharose FF). For example, 1.5 mg protein/ml gel is loaded on the column equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using an appropriate MW cutoff membrane. The preparation is next analytically characterized by measuring total protein (Coomassie, Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 1 is carried out as follows. Prolia is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 10 mg rFIX is dissolved in 5 ml histidine—buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 100 μl of an aqueous sodium periodate solution (5 mM) is then added and the reaction mixture is incubated for 1 h in the dark at 4° C. under gentle stirring and quenched for 15 min at room temperature by the addition of 50 μl of a 1 M aqueous cysteine solution. The mixture is subsequently subjected to UF/DF employing Vivaspin 15R 10 kD centrifugal filtrators to remove excess periodate, quencher and the byproducts thereof.

The retentate (approx. 7 ml), containing oxidized Prolia, is mixed with 2 ml of an aqueous m-toluidine solution (50 mM) and incubated for 30 min at room temperature. Then aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. This mixture is incubated for 2.5 h at RT in the dark under gentle stirring.

Finally the PEG-Prolia conjugate is purified by ion-exchange chromatography on SP Sepharose FF. The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SP FF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free Prolia is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PEG-Prolia conjugate a specific activity of >50% in comparison to native Prolia is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free Prolia.

Method 2:

Prolia is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). Prolia is transferred or dissolved in reaction buffer (e.g. 50 mM Hepes, 350 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 1.0+/−0.25 mg/ml. Then the pH of the solution is corrected to 6.0 by drop wise addition of a 0.5N aqueous HCl solution. Subsequently, a 40 mM aqueous sodium periodate solution is added within 10 minutes to give a concentration of 200 μM. The oxidation reaction is carried out for 30+/−5 min at a temperature (T) of T=+22+/−2° C. Then the reaction is stopped by addition of an aqueous L-cysteine solution (1 M) within 15 minutes at T=+22+/−2° C. to give a final concentration of 10 mM in the reaction mixture and incubation for 60+/−5 min.

The oxidized Prolia is further purified by ion exchange chromatography. The oxidized Humira containing fractions of the eluate are collected and used for the conjugation reaction.

The aminooxy-PEG reagent with a MW of 20 kD reagent is added in a 50-fold molar excess to the eluate containing the purified oxidized Prolia within a maximum time period (t) of 15 minutes under gentle stirring. Then an aqueous m-toluidine solution (50 mM) is added within 15 minutes to get a final concentration of 10 mM. The reaction mixture is incubated for 120+/−10 min. in the dark at a temperature (T) of T=+22+/−2° C. under gentle shaking.

The obtained PEG-Prolia conjugate is further purified by ion exchange chromatography. The PEG-Prolia conjugate containing fractions are collected and concentrated by ultra-/diafiltration (UF/DF) using a membrane made of regenerated cellulose with an appropriate molecular weight cut off (Millipore).

Method 3:

Prolia is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). EPO is dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) and mixed with an aqueous sodium periodate solution (10 mM), and an aqueous m-toluidine solution (50 mM). Subsequently the aminooxy reagent is added to give a 20-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 8 μl of aqueous cysteine solution (1 M).

Finally, the PEG-Prolia conjugate is purified by ion-exchange chromatography on Q-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column pre equilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl 2 ). The conjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl 2 ) and 500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a membrane. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art.

In an alternative embodiment, Method 3 is carried out as follows.

Prolia is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). 10 mg Prolia is dissolved in-8 ml histidine buffer, pH 6.0 (20 mM L-histidine, 150 mM NaCl). 200 μl of an aqueous sodium periodate solution (5 mM) and 2 ml of an aqueous m-toluidine solution (50 mM) are then added. Subsequently, the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 5-fold molar reagent excess. The mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of 100 μl of 1 M aqueous cysteine solution.

Finally the PEG-Prolia conjugate is purified by ion-exchange chromatography on SP-Sepharose FF. The reaction mixture is diluted with 20 ml Buffer A (50 mM Hepes, pH 6.5) and loaded onto a 20 ml HiPrep SPFF 16/10 column (GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Then the column is eluted with Buffer B (50 mM Hepes, 1 M NaCl, pH 6.5). Free Prolia is eluted by washing the column with 25% Buffer B and the conjugate at 50% Buffer B. The conjugate containing fractions are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against histidine buffer, pH 6.9 containing 150 mM NaCl. The preparation is analytically characterized by measuring total protein (Bradford) and biological activity according to methods known in the art. For the PEG-Prolia conjugate a specific activity of >50% in comparison to native Prolia is determined. The conjugate is additionally analytically characterized by Size Exclusion HPLC using a Agilent 1200 HPLC system equipped with a Shodex KW 803 column under conditions as previously described (Kolarich et al, Transfusion 2006; 46:1959-77). It is shown that the preparation contains no free Prolia.

Method 4:

Prolia is PEGylated by use of a linear 20 kD PEGylation reagent containing an aminooxy group. An example of this type of reagent is the Sunbright® CA series from NOF (NOF Corp., Tokyo, Japan). An initial concentration or weight of Humira is transferred or dissolved in Hepes buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH 6.0) to get a final protein concentration of 2 mg Prolia/ml. Subsequently a 5 mM aqueous sodium periodate solution is added within 15 minutes to give a final concentration of 100 μM, followed by addition of an 50 mM aqueous m-toluidine solution to get a final concentration of 10 mM within a time period of 30 minutes. Then the aminooxy-PEG reagent with a MW of 20 kD (described above) is added to give a 20-fold molar reagent excess. After correction of the pH to 6.0 the mixture is incubated for 2 h in the dark at room temperature under gentle stirring and quenched for 15 min at room temperature by the addition of an 1 M aqueous L-cysteine solution to give a final concentration of 10 mM.

The Prolia conjugate is purified by means of ion exchange chromatography (IEC). The conjugate containing fractions of the eluate are concentrated by UF/DF using a 10 kD membrane made of regenerated cellulose (88 cm2, cut-off 10 kD/Millipore). The final diafiltration step is performed against Hepes buffer (50 mM Hepes, 5 mM CaCl 2 ), pH 7.5).

The preparation is analytically characterized by measuring total protein (Bradford and BCA procedure) and biological activity according to known methods.

PEGylation of a Therapeutic Protein Using Branched PEG

PEGylation of a therapeutic protein of the invention may be extended to a branched or linear PEGylation reagent, which is made of an aldehyde and a suitable linker containing an active aminooxy group.