IUBMB Enzyme Nomenclature


Accepted name: pyroglutamyl-peptidase II

Reaction: Release of the N-terminal pyroglutamyl group from pGluHis-Xaa tripeptides and pGluHis-Xaa-Gly tetrapeptides

Other names: thyroliberinase; pyroglutamyl aminopeptidase II; thyrotropin-releasing factor pyroglutamate aminopeptidase; pyroglutamate aminopeptidase II; pyroglutamyl peptidase II; thyroliberin-hydrolyzing pyroglutamate aminopeptidase; thyrotropin-releasing hormone-degrading pyroglutamate aminopeptidase; thyrotropin-releasing hormone-degrading peptidase; TRH aminopeptidase

Comments: Highly specific for thyrotropin releasing hormone (pyroglutamyl-histidyl-prolylamide). Will not cleave the pyroglutamyl-histidyl bond of luteinizing hormone releasing hormone. Found in serum and brain. Inhibited by metal chelators. In peptidase family M1 (membrane alanyl aminopeptidase family)

Links to other databases: BRENDA, EXPASY, MEROPS, Metacyc, CAS registry number: 60063-88-9


1. Bauer, K. and Nowak, P. Characterization of a thyroliberin-degrading serum enzyme catalyzing the hydrolysis of thyroliberin at the pyroglutamyl-histidine bond. Eur. J. Biochem. 99 (1979) 239-246. [PMID: 115687]

2. O'Connor, B. and O'Cuinn, G. Purification of and kinetic studies on a narrow specifity synaptosomal membrane pyroglutamate aminopeptidase from guinea-pig brain. Eur. J. Biochem. 150 (1985) 47-52. [PMID: 2862039]

3. Wilk, S. and Wilk, E.K. Pyroglutamyl peptidase II, a thyrotropin releasing hormone degrading enzyme: purification and specificity studies of the rabbit brain enzyme. Neurochem. Int. 15 (1989) 81-89

[EC created 1992]

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