Glucosyl transferase activity of bovine galactosyl transferase.
Bovine galactosyl transferase was found to utilize UDPglucose as a substrate and elicit disaccharide biosynthesis with glucose and N-acetylglucosamine as acceptors. The relative rate of glucosyl transferase with N-acetylglucosamine as acceptor was 0.3%, the rate for N-acetyllactosamine biosynthesis. This activity was also evidenced indirectly from NMR water proton relaxation experiments, and from Mn(II) ESR experiments. In direct experiments with radioactive UDPglucose, paper chromatography showed a product which migrated with cellobiose when glucose was the acceptor and a new, glucose-containing product which resulted when GlcNAc was the acceptor. Despite this marginally expanded specificity of the donor site, spin-label experiments with a covalently bound UDPgalactose analog reaffirmed the restrictive nature of the donor site against this non-glycosyl-like analog.
D000818:Animals; D001665:Binding Sites; D001894:Borohydrides; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D005700:Galactosyltransferases / Q000378:metabolism*; D007700:Kinetics; D008892:Milk / Q000201:enzymology; D013379:Substrate Specificity; D013816:Thermodynamics; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
D001894:Borohydrides; D005700:Galactosyltransferases; D014532:Uridine Diphosphate Glucose