Transglycosylation Activity of Mucor Hiemalis Endo-β-N-Acetylglucosaminidase Which Transfers Complex Oligosaccharides to the N-Acetylglucosamine Moieties of Peptides

A novel endo-β-N-acetylglucosaminidase in the culture fluid of Mucor hiemalis isolated from soil was found to have transglycosylation activity. This endo-β-N-acetylglucosaminidase, Endo-M, could liberate the complex type of asparagine-linked oligosaccharides by hydrolysis of diacetylchitobiose linkage from glycoproteins. The treatment of Endo-M with N-acetylglucosamine and asialotransferrin glycopeptide having the complex type of oligosaccharides resulted in the transfer of the released oligosaccharide from the glycopeptide to N-acetylglucosamine. The structure of the product after transfer was deduced to be (GlcNAc)2-Man-(Gal-GlcNAc-Man)2 by a combination method of pyridylamination and high perfomance liquid chromatography, and mass-spectrometry. The enzyme could transfer the complex type of oligosaccharide from asialotransferrin glycopeptide to peptidyl-N-acetylglucosamine prepared from bovine ribonuclease with the high-mannose type of oligosaccharide. This will lead to the construction of neoglycoproteins containing different types of oligosaccharides.