Glutamyltransferase and glutaminyltransferase are different in the existence site, normal value, clinical significance and so on, as follows. 1. Existence site: Glutamyltransferase is an enzyme that catalyzes the transfer of γ-glutamyl group from glutathione to another peptide or another amino acid, and it mainly exists in cell membranes and microsomes. It is more abundant in the heart, liver, kidney and other organs, especially the liver is the most abundant. Glutaminase is distributed in liver, skeletal muscle, kidney, heart muscle and other tissues, especially the liver is the most abundant. 2. Normal reference value: The normal value of glutamyltransferase is between 9 and 50 U/L, while the normal value of alanine aminotransferase is between 5 and 40 U/L, and the reference range varies with different measurement methods. 3. Clinical significance: the decrease of both single indexes is generally of little significance, and the clinical significance of the increase is mainly considered. Elevated glutamyltransferase can be seen in physiological factors such as irregular diet and alcohol consumption, as well as pathological factors such as viral hepatitis, biliary obstruction and pancreatitis. Elevated glutamyltransferase is associated with physiologic causes such as late nights, alcohol consumption, and stress, as well as pathologic causes such as viral hepatitis, cirrhosis, dermatomyositis, and renal infarction.