Clinical Chemistry - Lactate Dehydrogenase

Lactate dehydrogenase (LD) catalyses the interconversion of lactic acid and pyruvic acid. The enzyme is composed of 4 peptide chains and exists in 5 isomeric forms. LD is widely distributed throughout the body, and the highest concentrations are found in the liver, heart and skeletal muscle. LD activity is significantly elevated during myocardial infarction. Maximum levels are reached 24 to 48 hours after the onset of chest pain and may remain elevated for 7 to 12 days post infarction. Increases in LD activity are also associated with other pathological conditions including liver disease, progressive muscular dystrophy, megaloblastic and pernicious anaemia