Patent ID: 7947473

Claim:
A method for producing an hGH-PEG conjugate comprising the steps: (a) reacting hGH comprising a non-naturally encoded keto amino acid with a derivatized polyethylene glycol (PEG) under conditions sufficient to covalently bond the keto amino acid to the PEG and to form the hGH-PEG conjugate wherein the non-naturally encoded keto amino acid is incorporated at position 35 in the hGH; and (b) isolating and purifying said hGH-PEG conjugate by contacting said hGH-PEG conjugate with an anion exchange matrix under conditions that allow binding of the hGH-PEG conjugate to the matrix followed by elution and collection of the hGH-PEG conjugate from the anion exchange chromatography matrix to provide substantially purified hGH-PEG conjugate.