Glutaminyl-peptide cyclotransferase

In enzymology, a glutaminyl-peptide cyclotransferase is an enzyme that catalyzes the chemical reaction


 * L-glutaminyl-peptide $$\rightleftharpoons$$ 5-oxoprolyl-peptide + NH3

Hence, this enzyme has one substrate, L-glutaminyl-peptide, and two products, 5-oxoprolyl-peptide and NH3.

This enzyme belongs to the family of transferases, specifically the aminoacyltransferases. The systematic name of this enzyme class is L-glutaminyl-peptide gamma-glutamyltransferase (cyclizing). Other names in common use include glutaminyl-tRNA cyclotransferase, glutaminyl cyclase, and glutaminyl-transfer ribonucleate cyclotransferase.

Structural studies
As of late 2007, 8 structures have been solved for this class of enzymes, with PDB accession codes, , , , , , , and.