In old literature, it was called as serum glutamate oxaloacetate transaminase (SGOT). AST needs pyridoxal phosphate (vitamin B6) as co-enzyme. Normal serum level of AST ranges from 8 to 20 U/L. It is a marker of liver injury and shows moderate to the drastic increase in parenchymal liver diseases like hepatitis and malignancies of the liver.Ref: DM Vasudevan, Page no: 269