This method describes the use of subtilisin-catalyzed peptide condensation to form a 15-residue glycopeptide from two smaller synthetic peptides. A 12-residue peptide ester is synthesized by solid-phase peptide synthesis using a PAM-modified Rink amide resin that allows the formation of a peptide ester suitable for subtilisin ligation. The 12-residue acyl donor peptide ester is then ligated to a 3-residue acyl acceptor glycopeptide amide using subtilisin (EC 3.4.21.62) in a buffered mixture of water and DMF (1:9).
