Lactate Dehydrogenase

Literature References: Enzyme found in almost all animal tissues, in microorganisms, and in plants. Isoln from heart muscle, rat skeletal muscle, and Jensen sarcoma: Straub, Biochem. J. 34, 483 (1940); Kubowitz, Ott, Biochem. Z. 314, 94 (1943); Meister, Biochem. Prep. 2, 18 (1952). Catalyzes the equilibrium reaction of pyruvic acid to lactic acid. Plays an important role in the equilibrium of carbohydrate catabolism and anabolism. Used as fuel for aerobic tissues such as the heart. Structure is a tetramer of mol wt about 140,000. Consists of units of mol wt about 35,000. Two types of subunits are distinguishable: M (muscle) type and H (heart) type. Lactate dehydrogenases of heart and muscle are mainly H4 and M4; all other possible hybrids have been found in various tissues. Elevations of lactate dehydrogenase activity have been found in myocardial infarction, hepatocellular necrosis, metastatic carcinoma, diabetic ketosis, sickle cell anemia, malignant lymphoma, infectious mononucleosis, and cerebral infarction: Standjord et al., J. Am. Med. Assoc. 182, 1099 (1962). Comprehensive reviews: Everse, Kaplan, Adv. Enzymol. Relat. Areas Mol. Biol. 37, 61 (1973); Holbrook et al., in The Enzymes vol. XI (part A), P. D. Boyer, Ed. (Academic Press, New York, 3rd ed., 1975) pp 191-292.