An enzyme transferring amino groups from L-alanine to 2-ketoglutarate, or the reverse (from L-glutamate to pyruvate); there is a D-alanine transaminase that effects the same reaction, but with D-alanine and D-glutamate. Used in clinical diagnosis of viral hepatitis and myocardial infarction. Syn: alanine transaminase, glutamic-pyruvic transaminase, serum glutamic-pyruvic transaminase.