Pyruvate + NADH + H+ <=> (S)-Lactate + NAD+ Cytosolic lactate dehydrogenase catalyzes the reversible reaction of pyruvate and NADH + H+ to form lactate and NAD+. In the body under anaerobic conditions such as are found in red blood cells or rapidly exercising skeletal muscle, this reaction regenerates NAD+, allowing the continuation of glycolysis.<p>Lactate dehydrogenase is active as a tetramer. Two isoforms of lactate dehydrogenase, A and B, are widely expressed in human tissues, and all five tetramers - A4, A3B, A2B2, AB3, and B4 - are found. A third isoform, C, and its tetramer, C4, are found in testis. EC Number: 1.1.1.27 Pubmed11276087 Pubmed11377399 Pubmed3435492 Reactome Database ID Release 4371849 Reactome, http://www.reactome.org ReactomeREACT_178