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. [provided by RefSeq, Jul 2008],catalytic activity:(5-L-glutamyl)-peptide + an amino acid = peptide + 5-L-glutamyl amino acid.,function:Cleaves glutathione conjugates.,pathway:Sulfur metabolism; glutathione metabolism.,similarity:Belongs to the gamma-glutamyltransferase family.,subunit:Heterodimer composed of the light and heavy chains. The active site is located in the light chain (By similarity). Isoform 3 interacts with FAM57A.,tissue specificity:Widely expressed, but at low level, except in the airway epithelial cells. Detected in brain, heart, kidney, liver, lung, spleen, testis and trachea.,