Serum ALT

The hepatic metabolite oxaloacetate is produced by the catalytic transfer of amino groups, which is carried out by the enzyme alanine aminotransferase (ALT). It is composed of 496 amino acids, which are encoded by a gene located on the elongated arm of chromosome 8. ALT is prevalent in the cytoplasm of hepatocytes. Thus, in the event of hepatocellular injury or death, Serum ALT activity is increased when injured liver cells release ALT. Contrary to popular belief, it is also present in the nephrons, the heart, and skeletal muscle cells, but in much smaller concentrations. It is thought to be only present in the liver. The liver catabolizes ALT, giving it a plasma half-life of 47 ~ 10 h, which is noticeably longer than AST’s (17 ~ 5 h). Daily variations in ALT activity range from 10% to 30%. Within a single day, there is significant diurnal variation; in the afternoon, ALT activity can be up to 45% higher than in the early morning.

ALT levels in the blood serum can efficiently indicate...