摘要 |
Processes for conjugating proteins with polyethylene glycol are disclosed. The disclosed processes provide modified proteins having little or no decrease in their activity and include the steps of protecting one or more sites on the protein, contacting the protected protein with polyethylene glycol under conditions suitable for conjugating the polyethylene glycol to the protein, and deprotecting the protein. This advantageous retention of a desired protein activity is attributed to the availability of one or more protein binding sites which is unaltered in the conjugation process and thus remains sterically free to interact with a binding partner ligand or cognate subsequent to the conjugation process. |