title: Porcine submaxillary mucin contains alpha 2----3- and alpha 2----6-linked N-acetyl- and N-glycolylneuraminic acid.
abstract: Four acidic trisaccharides have been obtained by alkaline borohydride reductive cleavage (beta-elimination) of a fraction of porcine submaxillary mucin precipitating at 60-75% ethanol. Their structures have been investigated using the techniques of methylation analysis involving gas-liquid chromatography/mass spectrometry along with high-resolution 1H-NMR analysis. Two of the four oligosaccharides, B1-B4, contain N-acetylneuraminic acid (NeuAc) while two contain N-glycolylneuraminic acid (NeuGc). The following structures are proposed for the acidic trisaccharide fraction: (B1) NeuAc alpha(2----3)Gal beta(1----3)GalNAcol, (B2) NeuGc alpha(2----3)Gal beta(1----3)GalNAcol, (B3) Gal beta(1----3)[NeuAc alpha(2----6)]GalNAcol and (B4) Gal beta(1----3)[NeuGc alpha(2----6)]GalNAcol, (GalNAcol = reduced N-acetylgalactosamine. These oligosaccharides were present in a molar ratio of 69:22:4:5. Although oligosaccharide B4 has previously been found in porcine submaxillary mucin B1, B2 and B3 have not. Furthermore, oligosaccharide B2 is a novel structure.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D009077:Mucins / Q000302:isolation & purification*; D009438:Neuraminic Acids / Q000032:analysis; D009844:Oligosaccharides / Q000032:analysis*; D012794:Sialic Acids / Q000032:analysis; D013363:Submandibular Gland / Q000032:analysis*; D013552:Swine
chemical_list: D009077:Mucins; D009438:Neuraminic Acids; D009844:Oligosaccharides; D012794:Sialic Acids; C032592:N-glycolylneuraminic acid