Application of Microbial Endoglycosidase for Glycotechnology

摘要

The oligosaccharides of some glycoconjugates play important roles in biological phenomena such as cellular recognition, immune responses, lectin binding and viral infection, among others. Progress in the field of glycobiology requires the synthesis of glycoconjugates to elucidate the significance and function of the oligosaccharide. The synthesis of new oligosaccharides with additional functions by modification of naturally occuring oligosaccharides, and the addition of an oligosaccharide to a substance to endow it with a useful function are important subjects in glycotechnology. However, no effective method for the binding of oligosaccharide to various substances is currently available. Recently, we developed a practical method for the addition of an oligosaccharide to a substance by means of the transglycosylation by microbial endoglycosidase, Endo-β-N-acetylglucosaminidase (endo-β-GlcNAc-ase) is a unique endoglycosidase that hydrolyzes N, N'-diacetylchitobiosyl linkages in oligosaccharides bound to asparaginyl residues of various glycoproteins and releases oligosaccharides. We found a novel endo-β-GlcNAc-ase in the culture fluid of Mucor hiemalis isolated from soil and named it Endo-M after its source. This enzyme showed transglycosylation activity and could transfer the intact oligosaccharide from glycopeptides to suitable acceptors with an N-acetylglucosamine (GlcNAc) residue during hydrolysis of the glycopeptide (1).