Specific detection of N-acetylglucosamine-containing oligosaccharide chains on ovine submaxillary asialomucin.
Human milk beta-N-acetylglucosaminide beta 1 leads to 4-galactosyltransferase (EC 2.4.1.38) was used to galactosylate ovine submaxillary asialomucin to saturation. The major [14C]galactosylated product chain was obtained as a reduced oligosaccharide by beta-elimination under reducing conditions. Analysis by Bio-Gel filtration and gas-liquid chromatography indicated that this compound was a tetrasaccharide composed of galactose, N-acetylglucosamine and reduced N-acetylgalactosamine in a molar ratio of 2:0.9:0.8. Periodate oxidation studies before and after mild acid hydrolysis in addition to thin-layer chromatography revealed that the most probable structure of the tetrasaccharide is Gal beta 1 leads to 3([14C]Gal beta 1 leads to 4GlcNAc beta 1 leads to 6)GalNAcol. Thus it appears that Gal beta 1 leads to 3(GlcNAc beta 1 leads to 6)GalNAc units occur as minor chains on the asialomucin. The potential interference of these chains in the assay of alpha-N-acetylgalactosaminylprotein beta 1 leads to 3-galactosyltransferase activity using ovine submaxillary asialomucin as an acceptor can be counteracted by the addition of N-acetylglucosamine.
D000117:Acetylglucosamine / Q000032:analysis*; D000818:Animals; D001212:Asialoglycoproteins; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005260:Female; D005944:Glucosamine / Q000031:analogs & derivatives*; D006801:Humans; D008895:Milk, Human / Q000201:enzymology; D009077:Mucins / Q000302:isolation & purification*; D009844:Oligosaccharides / Q000032:analysis*; D011247:Pregnancy; D012756:Sheep; D013363:Submandibular Gland / Q000032:analysis*; D006022:beta-N-Acetylglucosaminylglycopeptide beta-1,4-Galactosyltransferase / Q000378:metabolism
D001212:Asialoglycoproteins; D009077:Mucins; D009844:Oligosaccharides; D006022:beta-N-Acetylglucosaminylglycopeptide beta-1,4-Galactosyltransferase; D005944:Glucosamine; D000117:Acetylglucosamine