Abnormal Enzyme/Coenzyme Activity Elevated Serum Alanine Aminotransferase Alanine Aminotransferase Increased Sufficient An abnormally high concentration in the circulation of alanine aminotransferase (ALT), which is an enzyme that catalyzes the transfer of amino groups to form the hepatic metabolite oxaloacetate. ALT is found abundantly in the cytosol of the hepatocyte. ALT activity in the liver is about 3000 times that of serum activity. Thus, in the case of hepatocellular injury or death, release of ALT from damaged liver cells increases measured ALT activity in the serum. Although it is generally thought to be specific to the liver, it is also found in the kidney, and, in much smaller quantities, in heart and skeletal muscle cells. Elevated serum ALT HP:0031964 Elevated Serum Glutamic-Pyruvic Transaminase SCDO:1000659