Human -Glutamylcyclotransferase belongs to the Transferases family, specifically the Aminoacyltransferase. Gamma-Glutamylcyclotransferase catalyzes the formation of 5-Pxoproline from Gamma-Glutamyl Dipeptides. It plays an important role in Glutathione Homeostasis. Gamma-Glutamylcyclotransferase induces the release of Cytochrome C from the mitochondria resulting in the induction of apoptosis.