NEUTRAL OLIGOSACCHARIDES OF BOVINE SUBMAXILLARY MUCIN - A COMBINED MASS-SPECTROMETRY AND H-1-NMR STUDY

Twenty-two neutral O-linked oligosaccharides ranging from monosaccharides to octasaccharides were identified in bovine submaxillary-gland-mucin glycoprotein by a combination of liquid secondary-ion mass spectrometry, methylation analysis and H-1-NMR. Only five of these have been previously detected in bovine submaxillary-gland mucin although several have been described from other sources of mucin. The structures include short linear sequences 3-linked to N-acetylgalactosaminitol (GalNAcol) and branched structures based on either a GlcNAc(beta-1 - 6)[Gal(beta-1 - 3)]GalNAcol or GlcNAc(beta-1 - 6)[GlcNAc(beta-1 - 3)]GalNAcol core region. Oligosaccharides not previously characterised from any source were the disaccharide GalNAc-alpha-1 - 6GalNAcol (GalNAc, N-acetylgalactosamine and the hexasaccharide GlcNAc(beta-1 - 6){GalNAc(alpha-1 - 3)[Fucalpha-1 - 2)]Gal(beta-1 - 4)GlcNAc(beta-1 - 3)}GalNAcol (Fuc, L-fucose). Oligosaccharides of the blood-group-A type have not been detected previously in bovine submaxillary-gland mucin although their occurrence on bovine gastric-mucosal glycoproteins has been established by classical immunochemical studies.