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
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
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
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
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
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
contrary to wild-type, mlr6793-disruptant cells cannot grow on pyridoxine, 4-pyridoxic acid or 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate as sole carbon and nitrogen source
contrary to wild-type, mlr6793-disruptant cells cannot grow on pyridoxine, 4-pyridoxic acid or 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate as sole carbon and nitrogen source
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
structure determined by molecular replacement, to 1. 55 A resolution. Residues Ser116, His137 and Glu149 are connected by a hydrogen bonding network forming a catalytic triad
mutant shows a showed a different pH optimum depending on the cosubstrate. With NAD+, the mutant shows very low activity with an optimum pH at 8.5 in the universal buffer. In contrast, the optimum pH is 5.5 with NADH
mutant shows a showed a different pH optimum depending on the cosubstrate. With NAD+, the mutant shows very low activity with an optimum pH at 8.5 in the universal buffer. In contrast, the optimum pH is 5.5 with NADH
Enzymes of vitamin B6 degradation. Purification and properties of isopyridoxal dehydrogenase and 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylic-acid dehydrogenase