Chemo-enzymatic synthesis of a bioactive peptide containing a glutamine-linked oligosaccharide and its characterization

A bioactive peptide containing a glutamine-linked oligosaccharide was chemo-enzymatically synthesized by use of the solid-phase method of peptide synthesis and the transglycosylation activity of endo-beta -N-acetylglucoeaminidase. Substance P, a neuropeptide, is an undecapeptide containing two L-glutamine residues. A substance P derivative with an N-acetyl-D-glucosamine residue attached to the fifth or sixth L-glutamine residue from the N-terminal region was chemically synthesized. A sialo complex-type oligosuccharide derived from a glycopeptide of hen egg yolk was added to the N-acetyl-D-glucosamine moiety of the substance P derivative using the transglycosylation activity of endo-beta -N-acetylglucosaminidase from Mucor hiemalis, and a substance P derivative with a sialo complex-type oligosaccharide attached to the L-glutamine residue was synthesized. This glycosylated substance P was biologically active. although the activity was rather low, and stable against peptidase digestion. The oligosaccharide moiety attached to the L-glutamine residue of the peptide was not liberated by peptide-N-4-(N-acetyl-beta -D-glucosaminyl) asparagine amidase F. (C) 2001 Elsevicr Science B.V. All rights reserved.