Open AccessThe Degradation of M and N Blood Group Glycoproteins and Glycopeptides with Alkaline Borohydride
Author(s) -
Lisowska E.
Publication year - 1969
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1969.tb00727.x
Subject(s) - glycopeptide , chemistry , sialic acid , threonine , biochemistry , glycoprotein , galactose , borohydride , fucose , pronase , serine , trypsin , catalysis , enzyme , antibiotics
The sialic acid‐free M and N substances and glycopeptides from their pronase digest were treated with alkaline borohydride and products of degradation were fractionated. Galactose and N ‐acetylgalactosamine were split off during the degradation in the form of disaccharide: galactosyl‐ N ‐acetylgalactosaminitol, and it was accompanied by the release of amino acid components. The conclusion has been drawn that a part of carbohydrate moiety of M and N substances represents trisaccharides: N ‐acetylneuraminyl–galactosyl– N ‐acetylgalactosamine, linked to serine and threonine residues in the peptide chain by an alkali‐labile O ‐glycosidic bond. The other type of oligosaccharides present in M and N substances is linked to peptide chain by an alkali‐stabile bond and includes mannose, fucose, N ‐acetylglucosamine, the rest of sialic acid and galactose. The degraded M′ and N′ glycoproteins (M and N glycoproteins free of N ‐acetylneuraminic acid) did not inhibit the hemagglutination by Vicia graminea phytoagglutinins. The degraded native M and N substances were inactive towards both anti‐M and anti‐N rabbit immune sera, and anti‐N phytoagglutinins from V. graminea , but they were still as good inhibitors of viral hemagglutination as untreated substances.