Specificity of a particulate glucosyltransferase in seedlings of Pisum sativum L. which catalyzes the formation of 5'-O-(beta-D-glucopyranosyl)pyridoxine

J Nutr Sci Vitaminol (Tokyo). 1982;28(4):359-66. doi: 10.3177/jnsv.28.359.

Abstract

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.

MeSH terms

  • Fabaceae / enzymology*
  • Glucosides*
  • Glucosyltransferases / antagonists & inhibitors
  • Glucosyltransferases / metabolism*
  • Kinetics
  • Plants, Medicinal*
  • Pyridoxine / analogs & derivatives*
  • Pyridoxine / biosynthesis
  • Substrate Specificity

Substances

  • Glucosides
  • 5'-O-(glucopyranosyl)pyridoxine
  • Glucosyltransferases
  • Pyridoxine