Studies on Vitamin B₆ Metabolism in Microorganisms

Abstract

It was found that a considerable amount of pyridoxal 5′-phosphate (pyridoxal-P) was formed from pyridoxine through the transphosphorylation by the cells of Escherichia freundii K-1 and that phenyl phosphate was more effective on the formation as phosphoryl donor substrate than p-nitrophenyl phosphate. The effects of these phenolic compounds on the enzymes concerning with the conversion of pyridoxine to pyridoxal-P were studied. Then it was suggested that the more stimulating effect of phenyl phosphate on the pyridoxal-P formation than p-nitrophenyl phosphate might be caused by less inhibition of phenol than p-nitrophenol on pyridoxine dehydrogenase. Calcium salt of the product was isolated and identified.