aspartate aminotransferase (AST) /aspär″tāt/ , an enzyme normally present in body serum and in certain body tissues, especially those of the heart and liver. This enzyme affects the intermolecular transfer of an amino group from aspartic acid to alpha-ketoglutaric acid, forming glutamic acid and oxaloacetic acid. The reaction is reversible. The enzyme is released into the serum because of tissue injury and thus may increase as a result of myocardial infarction and liver damage. Normal findings for adults are 8 to 20 U/L or 5 to 40 IU/L. Compare alanine aminotransferase. Formerly called glutamic oxaloacetic transaminase, serum glutamic-oxaloacetic transaminase.
