Serum levels of the mitochondrial isoenzym of aspartate aminotransferase in myocardial infarction and muscular dystrophy.

Aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1, glutamic-oxalacetic transaminase, GOT) comprises two isoenzymes. One is anionic and is associated principally with the soluble fraction of the cytoplasm, the other is cationic and is associated with the mitochondria [4]. A sensitive semi quantitative assay has been developed for cationic aspartate aminotransferase in serum or plasma and it has been demonstrated that this isoenzyme is a normal constituent of plasma [5]. This paper is concerned with the changes in plasma level of the cationic isoenzyme occurring after myocardial infarction and in muscular dystrophy.