In enzymology, a gamma-glutamylcyclotransferase () is an enzyme that catalyzes the chemical reaction (5-L-glutamyl)-L-amino acid 5-oxoproline + L-amino acid Hence, this enzyme has one substrate, (5-L-glutamyl)-L-amino acid, and two products, 5-oxoproline and L-amino acid. This enzyme belongs to the family of transferases, specifically the aminoacyltransferases. The systematic name of this enzyme class is (5-L-glutamyl)-L-amino-acid 5-glutamyltransferase (cyclizing). Other names in common use include gamma-glutamyl-amino acid cyclotransferase, gamma-L-glutamylcyclotransferase, and L-glutamic cyclase. This enzyme participates in glutathione metabolism. Structural studies As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and . References EC 2.3.2 Enzymes of known structure