Pyrrolidone carboxyl peptidase (EC 3.4.11.8) is an exopeptidase commonly called PYRase, which hydrolytically removes the pGlu-proteins. pGlu also known as pyrrolidone carboxylic acid may occur naturally by an enzymatic procedure or may occur as an artifact in proteins or peptides. The enzymatic synthesis of pGlu suggests that this residue may have important biological and physiological functions. Several studies are consistent with this supposition. PYRase has been found in a variety of bacteria, and in plant, animal, and human tissues. For over two decades, biochemical and enzymatic properties of PYRase have been investigated. At least two classes of PYRase have been characterized. The first one includes the bacterial and animal type I PYRases and the second one the animal type II and serum PYRases. Enzymes from these two classes present differences in their molecular weight and in their enzymatic properties. Recently, the genes of PYRases from four bacteria have been cloned and characterized, allowing the study of the primary structure of these enzymes, and their over-expression in heterelogous organisms. Comparison of the primary structure of these enzymes revealed striking homologies. Type I PYRases and bacterial PYRases are generally soluble enzymes, whereas type II PYRases are membrane-bound enzymes. PYRase II appears to play as important a physiological role as other neuropeptide degrading enzymes. However, the role of type I and bacterial PYRases remains unclear. The primary application of PYRase has been its utilization for some protein or peptide sequencing. Development of chromogenic substrates for this enzyme has allowed its use in bacterial diagnosis.
The gene pcp, encoding pyrrolidone carboxyl peptidase (Pcp), from Pseudomonasfluorescens MFO was cloned and its nucleotide sequence was determined. This sequence contains a unique open reading frame (pcp) coding for a polypeptide of 213 amino acids (Mr 22,441) which has significant homology to the Pcps from Streptococcus pyogenes, Bacillus subtilis, and Bacilus amyloliquefaciens. Comparison of the four Pcp sequences revealed two highly conserved motifs which may be involved in the active site of these enzymes. The cloned Pcp from P. fluorescens was purified to homogeneity and appears to exist as a dimer. This enzyme displays a Michaelis constant of 0.21 mM with L-pyroglutamyl-,1-naphthylamide as the substrate and an absolute substrate specificity towards N-terminal pyroglutamyl residues. Studies of inhibition by chemical compounds revealed that the cysteine and histidine residues are essential for enzyme activity. From their conservation in the four enzyme sequences, the Cys-144 and His-166 amino acids are proposed to form a part of the active site of these enzymes.Pyrrolidone carboxyl peptidases (Pcps) (EC 3.4.11.8) are aminopeptidases that selectively remove amino-terminal Lpyroglutamic acid (Pyr) from peptides and proteins (15). These enzymes are present in many bacteria (30) and also in plant, animal, and human tissues (40).Preliminary studies of Pcps have consisted of purification of these enzymes from different bacterial strains (1,24,39,41,43) with a view to using them in protein sequencing to unblock proteins and polypeptides with an N-terminal pyroglutamyl residue prior to sequential Edman degradation (16). These bacterial Pcps, which are cysteine peptidases, showed an absolute specificity for pyroglutamyl residues located at the N terminus of peptides (41, 43) and for chromogenic substrates, such as L-pyroglutamyl-,B-naphthylamide (Pyr-3NA) (41), pyroglutamyl-p-nitroanilide, and pyroglutamyl-4-methylcoumarinylamide (17).Mammalian Pcps were later analyzed and shown to be involved in hormonal and neuronal metabolism (6,8,44). Two different types of Pcps have been detected in mammals. The first, which is a metallopeptidase, is specific for the pyroglutamyl-neuropeptide thyrotropin-releasing hormone (Pyr-HisPro-NH2) and is responsible for regulating the concentration of this neuropeptide (13,31,32). The second is a cysteine peptidase with a general specificity for N-terminal pyroglutamyl residues (7, 10). This Pcp, the function of which has not yet been determined, seems to be more closely related to bacterial Pcps than the first with respect to size, substrate specificity, and sensitivity to inhibitors.Recently, the structural genes encoding Pcps from the gram-positive bacteria Streptococcus pyogenes (12), Bacillus subtilis (3), and Bacillus amyloliquefaciens (45) have been cloned and characterized. The three deduced amino acid sequences are strongly homologous and display long conserved domains. The absence of homology with other peptidases suggests that these Pcps belong to a new class of peptidases * ...
Pyrrolidone carboxyl peptidasc (EC 3.4.11.8) (Pep) is an enzyme that catalyzes the removal of the N-terminal pyroglutamyl group from some peptidcs or proteins. Its value in protein chemistry and bacterial diagnosis makes this enzyme an interesting subject of study. The present paper reports for the first time the cloning and characterization of a pyrrolidone carboxyl peptidase gcnc (pep). This gcnc is present in a single copy in the gcnome of Bucilluv sul~rifir as indicated by Soulhcrn blot hybridization analysis, The pep transcripts were analyzed in Escherfchia coti by Northern blot hybridization and S1 nuclcass mapping. The deduced amino acid sequence predicts a protein of 215 amino acids with a calculated molecular weight of 23,777 Da. The pep gene has been over-expressccl in B coli, allowing the identification and parti41 charactcrieation of Pep prodn.
P),rrotidonc earboxyl wptidase (EC 3.4.11.8) (Pep). an enzyme which =lectivdy removes pyrrolidone earboxyli¢ acid (FCA) from mine PCApeptid~ and .proteins, was demonstrated in bacteria and in plant, animal and human tissues. In this pa~r we dear;be the purification to homol~neity of the enzyme of Sueptaracrus pyuxenes, over.expressed in F.~cherlchit~ coil This was achieved, for the first time in one step. by hydrophobic interaction chromatoliraphy. Analysis under non.deaaturing conditions revealed a mol~ular mo~ of t~$ kDa and in the pre".,=nce or sodium dodceyl sulfate lave u molecular mass ©f 23.5 kDa. inve=ti@tions on enzymatic properti~ showed that the Pep over.expressed in F~ rail disclosed prot~rti¢~ similar to thor< found for the enzyme ~tracted from $, Rrt~gr.es or for some other Peps studied previoudy, Thus the over.expr~sed enzym¢ should serve at ;t =;uitable ¢our~ for N.terminal unbloeking prior to ~m¢ PCA protein ~quencing,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.