TRANSGLYCOSYLATION OF INTACT SIALO COMPLEX-TYPE OLIGOSACCHARIDES TO THE N-ACETYLGLUCOSAMINE MOIETIES OF GLYCOPEPTIDES BY MUCOR HIEMALIS ENDO-BETA-N-ACETYLGLUCOSAMINIDASE

The endo-beta-N-acetylglucosaminidase (endo-beta-GlcNAc-ase) of Mucor hiemalis, endo-M, was found to transfer the sialo complex-type oligosa ccharides from transferrin glycopeptide to the N-acetylglucosamine (Gl cNAc) moieties of peptidyl-GlcNAc, Disialo complex-type oligosaccharid e of transferrin glycopeptide was transferred to 9-fluorenylmethyloxyc arbonyl (Fmoc)-asparaginyl-N-acetylglucosaminide (Fmoc-Asn-GlcNAc) by endo-M in a high yield. The structure of the reaction product was conf irmed to be Fmoc-Asn-(GlcNAc)(2)-Man-(Man-GlcNAc-Gal-NeuAc)(2) by mass spectrometry. Endo-M also transferred disialo complex type oligosacch aride to the GlcNAc residue of chemically synthesized H-Ile-Asn(GlcNAc )-Ala-Thr-Leu-OH. Asn-linked asialo complex-type oligosaccharide and A sn-linked high-mannose type oligosaccharide were also effective as oli gosaccharide donors, Transfer of disialo complex-type oligosaccharide to the GlcNAc-peptide was the most effective among the three types of oligosaccharides, although the disialo complex-type oligosaccharide at tached to the peptide was the poorest substrate for the hydrolytic act ivity of endo-M. (C) 1996 Elsevier Science Ltd.