Lactate dehydrogenase (LDH) is an enzyme (EC1.1.1.27) present in a wide variety of organisms, including plants and animals.A tetrameric enzyme that catalyses the interconversion of pyruvateand lactatewith concomitant interconversion of NADH and NAD+. At high concentrations of pyruvate, the enzyme exhibits feedback inhibition and the rate of conversion of pyruvate to lactate is decreased. In vertebrates, genes for three different subunits (LDH-A, LDH-B and LDH-C) exist Synonyms: Lactate Dehydrogenase, LDH.