alanine aminotransferase (ALT), an enzyme normally present in the serum and tissues of the body, especially the tissues of the liver. This enzyme catalyzes the transfer of an amino group from alanine to alpha-ketoglutarate, forming pyruvate and glutamate. The reaction is reversible. The enzyme is released into the serum as a result of tissue injury and increases in persons with acute liver damage. Normal findings are 5 to 35 IU/L. Also called alanine transferase. Compare aspartate aminotransferase.
