Specificity of a particulate glucosyltransferase in seedlings of Pisum sativum L. which catalyzes the formation of 5'-O-(beta-D-glucopyranosyl)pyridoxine.
A glucosyltransferase, catalyzing the transfer of D-glucose from UDP-glucose to the 5'-hydroxyl group of pyridoxine, was isolated as a particulate enzyme from seedlings of podded pea (Pisum sativum L. cv. Kinusaya). The enzyme required additional Mg2+ for its function. The pH optimum for glucosylation of pyridoxine was between 7.8 and 8.8. The enzyme showed high specificity for UDP-glucose and relative specificity for glucosyl acceptor: pyridoxine was replaceable by pyridoxamine. Several compounds tested other than vitamin B6 failed to serve as the acceptor. It was shown that a methylene group on C-4 participated in the formation of enzyme-substrate complex, and that the rate of glucosylation was dependent upon the C-4 substituent. From the results of kinetic studies and an experiment in vivo, the enzyme was inferred to be UDP-glucose: pyridoxine 5'-O-beta-glucosyltransferase.
D007887:Fabaceae / Q000201:enzymology*; D005960:Glucosides; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007700:Kinetics; D010946:Plants, Medicinal; D011736:Pyridoxine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D013379:Substrate Specificity
D005960:Glucosides; C022945:5'-O-(glucopyranosyl)pyridoxine; D005964:Glucosyltransferases; D011736:Pyridoxine