Gamma-glutamyl transpeptidase is a membrane-bound protein that is important in the metabolism of glutathione. The protein is similar in sequence to several members of the gamma-glutamyl transpeptidase family.Gamma-glutamyl transpeptidase is a membrane-bound protein that is important in the metabolism of glutathione. The protein encoded by this gene is similar in sequence to several members of the gamma-glutamyl transpeptidase family. Three transcript variants encoding the same protein have been found for this gene.