The role of alanine aminotransferase is to participate in metabolism and to serve as an indicator of liver impairment, etc. The role of glutamyl transferase is to participate in metabolism and to identify and diagnose other diseases. 1. Role of alanine aminotransferase: (1) Participation in metabolism: alanine aminotransferase is indirectly involved in the process of glucose metabolism. It can catalyze glutamate and alanine, and alanine is the intermediate carrier of glucose metabolism in the human body, so the role of alanine aminotransferase has to participate in metabolism. (2) Indicator of liver function damage: alanine aminotransferase mainly exists in liver cells, destruction of liver cells will cause alanine aminotransferase to rise, suggesting liver function damage. 2. Role of glutamyltransferase: (1) Involved in metabolism: glutamyltransferase is mainly involved in the metabolism of glutathione and the metabolism of proteins in the body. (2) Identification and diagnosis of other diseases: glutamyltransferase is mainly found in the liver, and its role in reacting to liver function damage is not as good as that of alanine aminotransferase, but it has a certain role in identification of jaundice and diagnosis of cirrhosis and other diseases.