aminotransferase /-trans″fərās/ , enzymes that catalyze the transfer of an amino group from an amino acid to an alpha-keto acid, with pyridoxal phosphate and pyridoxamine phosphate acting as coenzymes. Aspartate aminotransferase (AST), normally present in serum and various tissues, especially in the heart and liver, is released by damaged cells, and as a result, a high serum level may be diagnostic of myocardial infarction or hepatic disease. Alanine aminotransferase, a normal constituent of serum, especially in the liver, is released by injured tissue and may be present in high concentrations in the sera of patients with acute liver disease. Formerly called transaminase.
