PLP catabolism: Identification of the 4-pyridoxic acid dehydrogenase gene in Mesorhizobium loti MAFF303099

The gene encoding 4-pyridoxic acid dehydrogenase, a PLP catabolic enzyme, was identified and the corresponding protein overexpressed and characterized. This 33 kDa enzyme catalyzes the four electron oxidation, by NAD, of 4-pyridoxic acid to 3-hydroxy-2-methylpyridine-4,5-dicarboxylate. No accumulation of the aldehyde intermediate was detected.