1.2.1.100 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate + NAD+ + H2O - Pseudomonas sp. MA-1 3-hydroxy-2-methylpyridine-4,5-dicarboxylate + NADH + H+ - ? 442217 1.2.1.100 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate + NAD+ + H2O - Mesorhizobium loti 3-hydroxy-2-methylpyridine-4,5-dicarboxylate + NADH + H+ - ? 442217 1.2.1.100 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate + NAD+ + H2O - Mesorhizobium japonicum 3-hydroxy-2-methylpyridine-4,5-dicarboxylate + NADH + H+ - ? 442217 1.2.1.100 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate + NAD+ + H2O - Mesorhizobium loti MAFF303099 3-hydroxy-2-methylpyridine-4,5-dicarboxylate + NADH + H+ - ? 442217 1.2.1.100 additional information enzyme catalyzes oxidation of the hemiacetal form of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate to 3-hydroxy-2-methylpyridine-4,5-dicarboxylate with NAD+ and reduction of an aldehyde form of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate to 4-pyridoxic acid with NADH, i.e. reaction of 4-pyridoxic acid dehydrogenase. The Ser-His-Glu catalytic triad facilitates the two-way reactions. Ser116 assists protonation of His137 to drive the reduction reaction. His137 acts as a catalytic base to abstract a proton during oxidation. Glu149 likely neutralizes the positive charge on His137 after the deprotonation of the substrate Mesorhizobium japonicum ? - ? 89 1.2.1.100 additional information enzyme catalyzes practically irreversible oxidation of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate by NAD+ to 3-hydroxy-2-methyl-pyridine 4, 5-dicarboxylic acid, and practically irreversible reduction of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate by NADH to 4-pyridoxic acid, i.e. reaction of EC 4-pyridoxic acid dehydrogenase. When the enzyme reaction is started with the combination of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate and NAD+ or that of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate and NADH, 3-hydroxy-2-methylpyridine-4,5-dicarboxylate and 4-pyridoxic acid are produced in an almost equimolar ratio throughout the reaction Mesorhizobium loti ? - ? 89 1.2.1.100 additional information enzyme catalyzes with equal facility both the oxidation of formyl-3-hydroxy-2-methylpyridine-4-carboxylic-acid by NAD+ to 3-hydroxy-2-methylpyridine-4,5-dicarboxylic acid and the reduction of formyl-3-hydroxy-2-methylpyridine-4-carboxylic-acid by NADH to 4-pyridoxic acid, i.e. reaction of 4-pyridoxic acid dehydrogenase. No oxidation of 4-pyridoxic acid is observed Pseudomonas sp. MA-1 ? - ? 89 1.2.1.100 additional information enzyme catalyzes practically irreversible oxidation of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate by NAD+ to 3-hydroxy-2-methyl-pyridine 4, 5-dicarboxylic acid, and practically irreversible reduction of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate by NADH to 4-pyridoxic acid, i.e. reaction of EC 4-pyridoxic acid dehydrogenase. When the enzyme reaction is started with the combination of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate and NAD+ or that of 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate and NADH, 3-hydroxy-2-methylpyridine-4,5-dicarboxylate and 4-pyridoxic acid are produced in an almost equimolar ratio throughout the reaction Mesorhizobium loti MAFF303099 ? - ? 89