Biochemistry & Analytical Biochemistry

Abstract

Serum Transaminases: Quo Vadis

Preetam Nath and Shivaram Prasad Singh

Serum transaminases (also called aminotransferases) are basically enzymes in the human body which help in catalyzing reactions involving transfer of the α-amino groups. Alanine transaminase (ALT) helps in conversion of alanine into pyruvate and Aspartate transaminase (AST) helps in formation of α-ketoglutarate from aspartate . Both AST and ALT are sensitive markers of acute hepatocellular injury and are routinely used to identify liver disease since 1955. Both are readily available, inexpensive, and routinely assayed in clinical practice. AST which was formerly known as serum glutamic oxaloacetic transaminase (SGOT), is found in both cytosol and mitochondria in several organs such as the liver, cardiac muscle, skeletal muscle, kidney, brain, pancreas, lung, leukocytes, and erythrocytes but the concentration is highest in the hepatic parenchyma. On the contrary, ALT (formerly serum glutamic pyruvic transaminase or SGPT) is a cytosolic enzyme which is present predominantly in the liver. Hence ALT is a more specific indicator of liver injury than AST. Serum levels of these enzymes reflect injury of the concerned organs especially the liver. However, the degree of elevation of the serum transaminases may not correlate with the extent of liver injury.