Studies on vitamin B6 metabolism in microorganisms. XII. Glycolaldehyde synthesizing pathway involved in vitamin B6 biosynthesis in Escherichia coli B.

Abstract

Some enzymatic activities which may be possibly involved in biosynthesis of glycolaldehyde, a precursor of vitamin B6, were sought in the cell-free extracts of a wild type and a vitamin B0 auxotroph of Escherichia coli B. The cell-free extract from the auxotroph had no activity of NADP dependent glycolaldehyde dehydrogenase, while that of wild type strain showed enough of its activity. No significant difference in other possible enzymatic activities were observed between the two strains. Glycolaldehyde stimulates the growth of the auxotroph as pyridoxal does, while glycolate has no effect on it.From these results, it became apparent that glycolaldehyde is synthesized from glycolate in E. coli B and that glycolaldehyde dehydrogenase is genetically defective in the vitamin B6 auxotroph.