This gene is a member of a gene family that encodes enzymes involved in both the metabolism of glutathione and in the transpeptidation of amino acids. Changes in the activity of gamma-glutamyltransferase may signal preneoplastic or toxic conditions in the liver or kidney. The protein encoded by this gene consists of a heavy and a light chain, and it can interact with CT120, a plasma membrane-associated protein that is possibly involved in lung carcinogenesis.