Many glycosidases exhibit transglycosylation activities that involve the transfer of a carbohydrate moiety to the hydroxyl groups of various compounds, in addition to hydrolytic activities. We established the chemo-enzymatic synthesis of a glycopeptide using the transglycosylation activity of endo-β-
N-acetylglucosaminidase of
Mucor hiemalis (Endo-M). This method consists of the chemical synthesis of
N-acetylglucosaminyl peptide and the transglycosylation of N-linked sugar chain from oligosaccharide donor to an
N-acetylglucosaminyl peptide by Endo-M. We could add the sialo-complex-type oligosaccharide to bioactive peptides such as Peptide T and calcitonin by this method. We were also able to add the oligosaccharide to the glutamine residue of the Substance P neuropeptide and yeast α-mating factor. These glycosylated bioactive peptides showed a higher degree of resistance to protease digestion than original peptides.
By means of transglycosylation of Endo-M, we prepared glycopolymer containing multivalent oligosaccharides which can inhibit infection of influenza viruses to host cells. We also could exchange the high-mannose type of oligosaccharides in glycoproteins/glycopeptides to the complex types by the transglycosylation of Endo-M, and could synthesize novel glycolipids having a sugar chain of glycoprotein using the transglycosylation activity of Endo-M followed by preparation of a monoclonal antibody against the oligosaccharide of glycoprotein using the obtained glycolipid as immunogen.
Endo-α-
N-acetylgalactosaminidase from
Bifidobacterium longum exhibits transglycosylation activity. We succeeded in adding Galβ1, 3GalNAc from Galβ1, 3GalNAcα1
pNP to 1-alchanol, monosaccharide and bioactive peptides containing a serine/threonine residue using this enzyme.
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