Pyroglutamyl-peptidase I

{{Infobox enzyme

| Name = Pyroglutamyl-peptidase I

| EC_number = 3.4.19.3

| CAS_number = 9075-21-2

| GO_code =

| image =

| width =

| caption =

}}

Pyroglutamyl-peptidase I ({{EC number|3.4.19.3}}, also known as Pyrrolidonyl peptidase, is an enzyme (a cysteine peptidase) found in bacteria, plants and animals.

It can be used to distinguish certain Streptococcal organisms.{{cite journal |vauthors =Panosian KJ, Edberg SC |title=Measurement of constitutive L-pyrrolidonyl peptidase activity from Streptococcus and Enterococcus using tetrazotized 0-dianisidine |journal=Antonie van Leeuwenhoek |volume=55 |issue=3 |pages=269–75 |date=March 1989 |pmid=2569292 |doi= 10.1007/BF00393855}}

Other names are 5-oxoprolyl-peptidase, pyrase, pyrrolidonyl arylamidase, pyroglutamate aminopeptidase, pyroglutamyl aminopeptidase, L-pyroglutamyl peptide hydrolase, pyrrolidone-carboxyl peptidase, pyrrolidone-carboxylate peptidase, pyrrolidonyl peptidase, L-pyrrolidonecarboxylate peptidase, pyroglutamidase, pyrrolidonecarboxylyl peptidase) is an enzyme.{{cite journal | title = Pyroglutamyl-peptidase from Bacillus amyloliquefaciens. An improved purification method and some properties of the enzyme | vauthors = Tsuru D, Nakamura K, Yoshimoto T, Fujiwara K |journal = Biochim. Biophys. Acta |date = 1984 |volume = 791 |issue = 2 |pages = 117–122 |doi=10.1016/0167-4838(84)90001-3}}{{cite journal | vauthors = Awadé AC, Cleuziat P, Gonzalès T, Robert-Baudouy J | title = Pyrrolidone carboxyl peptidase (Pcp): an enzyme that removes pyroglutamic acid (pGlu) from pGlu-peptides and pGlu-proteins | journal = Proteins | volume = 20 | issue = 1 | pages = 34–51 | date = September 1994 | pmid = 7824521 | doi = 10.1002/prot.340200106 }}{{cite journal | vauthors = Patti JM, Schneider A, Garza N, Boles JO | title = Isolation and characterization of pcp, a gene encoding a pyrrolidone carboxyl peptidase in Staphylococcus aureus | journal = Gene | volume = 166 | issue = 1 | pages = 95–9 | date = December 1995 | pmid = 8529900 | doi = 10.1016/0378-1119(95)00561-0 }}{{cite journal | vauthors = Le Saux O, Gonzales T, Robert-Baudouy J | title = Mutational analysis of the active site of Pseudomonas fluorescens pyrrolidone carboxyl peptidase | journal = Journal of Bacteriology | volume = 178 | issue = 11 | pages = 3308–13 | date = June 1996 | pmid = 8655512 | pmc = 178084 }} This enzyme catalyses the following chemical reaction

: Release of an N-terminal pyroglutamyl group from a polypeptide, the second amino acid generally not being Pro