The enzymatic reduction of hydroxypyruvic acid to D-glyceric acid in higher plants.

Meister (1) has reported that the rate of reduction of hydroxypyruvate by reduced diphosphopyridine nucleotide (DPNH) in the presence of muscle lactic dehydrogenase is as rapid as the rate of reduction of pyruvate. The present paper reports evidence for the existence in higher plants of a new pyridine nucleotide dehydrogenase which catalyzes the reduction of hydroxypyruvate, but not of pyruvate. The product of this reaction has been identified as n-glyceric acid. The reaction, shown in Equation 1, is reversible, and the enzyme may therefore be called n-glyceric dehydrogenase. This enzyme does not act with lactic acid, and is consequently quite distinct from lactic dehydrogenase.