NoteEMcient Synthesis of a Sialyl T - antigen - } inked by the Chemoenzymatie Method Glycopeptide JSasA

glycopeptides are expected to greatly mediate their biological properties and functions.') The demand for easy synthesis of such peptides and proteins bearing sugar chains is thus increasing.2} The synthesis of N-linked glycopeptides has been performed by transglycosylating the entire structure of a high-mannose type or complex-type sugar chain to GlcNAc-linked peptides by utilizing endo N-acetylglucosaminidase A3) or M.`) In contrast, for the synthesis of O-linked glycopeptides, no versatile endo Nacetylgalactosaminidase is easily available at present. Therefore, organic chemical syntheses based on a solid-phase peptide synthesis are mainly employed,S,6) Howeyer, organic synthesis of the carbohydrate chain is timeconsuming due to the repeated protection and deprotection of hydroxyl groups in the carbohydrate units. It is a challenge at present to establish an eMcient and practical method for the synthesis of Olinked glycopeptides. We report here an eMcient ap-