Biosynthesis of vitamin B6 in rhizobium: In vitro synthesis of pyridoxine from 1-Deoxy-D-xylulose and 4-Hydroxy-L-threonine

Abstract

Pyridoxine (vitamin B6) in Rhizobium is synthesized from 1-deoxy-D-xylulose and 4-hydroxy-L-threonine. To define the pathway enzymatically, we established an enzyme reaction system with a crude enzyme solution of R. meliloti IFO14782. The enzyme reaction system required NAD+, NADP+, and ATP as coenzymes, and differed from the E. coli enzyme reaction system comprising PdxA and PdxJ proteins, which requires only NAD+ for formation of pyridoxine 5′-phosphate from 1-deoxy-D-xylulose 5-phosphate and 4-(phosphohydroxy)-L-threonine. © 2002 by Japan Society for Bioscience, Biotechnology, and Agrochemistry.