261c] Clinical aspects of aspartate and alanine aminotransferases

Abstract

This chapter discusses clinical aspects of aspartate and alanine aminotransferases. Aminotransferases are among a group of ubiquitous enzymes whose serum activity is elevated in many different disease states, including myocardial infarction, viral and toxic hepatitis, muscular dystrophy, and other muscular diseases, and in a small percentage of cancer patients, probably those with liver involvement. Electrophoretically separable isozymes have not been described for alanine aminotransferase, but have been described for the aspartate aminotransferase. All human tissues that have been studied by starch block electrophoresis have both cationic and anionic components of the aspartate aminotransferase. In normal human serum, however, only the anionic component was found. In some patients with elevated serum aspartate aminotransferase activity, the cationic component was also found. Both aspartate and alanine aminotransferase are found in bile and in saliva. Cerebrospinal fluid contains aspartate transaminase but little or no alanine transaminase. The frequency and extent of elevations of aspartate transaminase in various acute and chronic diseases are illustrated in several representative studies listed in the table.