title: Branch specificity of bovine colostrum and calf thymus UDP-Gal: N-acetylglucosaminide beta-1,4-galactosyltransferase.
abstract: The branch specificity of bovine colostrum and calf thymus UDP-Gal:N-acetylglucosaminide beta-1----4-galactosyltransferase toward several branched oligosaccharides, which form part of the complex-type N-glycans of glycoproteins, was investigated. A novel method was used based on acetolysis of the bi[14C,3H] galactosylated oligosaccharide products formed by the enzymes in vitro and analysis of the acetolysis fragments by high-pressure liquid chromatography. It could be established that the galactosylation of different oligosaccharide branches occurred in a preferred order. No difference in branch specificity was observed between the soluble bovine colostrum galactosyltransferase and the enzyme that had been solubilized from calf thymus membranes. A preferential pathway for the biosynthesis of bisialylated biantennary glycans is proposed.
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002250:Carbon Radioisotopes; D002417:Cattle; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003126:Colostrum / Q000201:enzymology*; D005260:Female; D007788:Lactose Synthase / Q000378:metabolism*; D009237:N-Acetyllactosamine Synthase / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism; D011247:Pregnancy; D013379:Substrate Specificity; D013950:Thymus Gland / Q000201:enzymology*; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D009844:Oligosaccharides; D014316:Tritium; D007788:Lactose Synthase; D009237:N-Acetyllactosamine Synthase