Reconstitution and Biochemical Characterization of a New Pyridoxal-5'-Phosphate Biosynthetic Pathway

摘要

Pyridoxal-5'-phosphate (PLP,vitamin B_6) is an essential cofactor in all living systems.It plays an important role in amino acid and carbohydrate metabolism and has recently been implicated in singlet oxygen resistance.The biosynthesis of PLP in Escherichia coli has been well studied.The enzymes PdxA and PdxJ catalyze the conversion of l-deoxy-D-xylulose-5-phosphate and 4-hydroxy-L-threonine to pyridoxine phosphate,which is then oxidized to PLP by PdxH.This pathway,however,is restricted to a relatively small number of bacteria,and most bacteria,archaebacteria,fungi,and plants do not contain PdxA/J/H homologues.