Polypeptide is an active substance that realizes various functions in organism. Polypeptide modification is mainly the modification of main chain structure and side chain groups.Modification can change the physical and chemical properties of peptide compounds and optimize their effective use in vivo.Modified polypeptide drugs can significantly reduce the immunogenicity, reduce toxicity, increase water solubility, prolong the time of action in vivo, change the distribution in vivo and so on.

    Common peptide modifications include c-terminal modification, n-terminal modification, side-chain modification, amino acid modification and skeleton modification.