Patent ID: 7265085

Claim:
A cell-free, in vitro method of forming a covalent conjugate of a peptide having the formula: wherein AA is a terminal or internal amino acid residue of said peptide; X 1 -X 2 is a saccharide covalently linked to said AA, wherein X 1 is a first glycosyl residue; and X 2 is a second glycosyl residue covalently linked to X 1 , wherein X 1 and X 2 are selected from monosaccharyl and oligosaccharyl residues; said method comprising: (a) removing X 2 or a saccharyl subunit thereof from said peptide, thereby forming a truncated glycan; and (b) contacting said truncated glycan with at least one glycosyltransferase and at least one modified sugar donor under conditions suitable for said at least one glycosyltransferase to transfer a modified sugar moiety of said at least one modified sugar donor to said truncated glycan, wherein said modified sugar moiety comprises at least one polymeric modifying group, thereby forming said covalent conjugate of said peptide.