Chemoenzymatic Synthesis of Neoglycopeptides Using Endo β- N -acetylglucosaminidase from Mucor hiemalis

Endo- β -N-acetylglucosaminidase is an enzyme that hydrolytically cleaves the N,N´ -diacetylchitobiose moiety of the asparagines N-linked oligosaccharide of various glycoproteins and releases intact oligosaccharides. This enzyme is a unique endoglycosidase that leaves one N-acetyl-d-glucosamine (GlcNAc) residue on the protein moiety. Several microbial endo- β -N-acetylglucosaminidases show the transglycosylation activity. Endo- β -N-acetylglucosaminidases of Arthrobacter protophormiae (Endo-A) and of mucor hiemalis (Endo-M) also show the transglycosylation activity. Endo-A acts on a high mannose-type oligosaccharide, whereas Endo-M acts on complex-type, high mannose-type, and hybrid-type oligosaccharides and can transfer the oligosaccharides from glycopeptides to suitable acceptors with a GlcNAc residue during hydrolysis of the glycopeptides. This chapter focuses on a chemoenzymatic synthetic method for a glycopeptides combined with the chemical synthesis of a peptide containing GlcNAc as a glycosylation tag and the transglycosylation catalyzed by Endo-M.