Site-specific PEGylation Strategies and Suitable Modified Sites of Protein Drugs

PEGylation,the covalent attachment of polyethylene glycol (PEG) to proteins,has been used as an effective strategy to overcome several shortcomings of proteins for therapeutic uses.The therapeutic efficacy of PEGylated protein drugs can be improved through prolonging their circulating half-life,reducing their immunogenicity and proteolysis,and increasing their stability and solubility.Furthermore,site-specific PEGylation is an attractive approach for the maximizing the bioavailability of drugs,because a homogeneously modified product with high activity retention and yield can be achieved.Recent advances in site-specific PEGylation were reviewed.The site-specific PEGylation strategies and suitable modified sites were particularly introduced.Finally,the future trends and prospects in site-specific PEGylation were discussed.