Pyroglutamyl peptidase

An exopeptidase that does not cleave standard peptide bonds. An example is pyroglutamyl-peptidase I (MEROPS C15.010), which releases an N-terminal pyroglutamyl from hormones such as thyrotropinreleasing hormone and luteinizing hormone. Omega peptidases are included in Enzyme Nomenclature subsubclass 3.4.19. 

This enzyme [EC 3.4.19.3], a member of the C15 peptidase family, is also known as pyroglutamyl-peptidase 1,5-oxoprolyl-peptidase, pyrrolidone-carboxylate peptidase, and pyroglutamyl aminopeptidase. This hydrolase catalyzes the conversion of a 5-oxoprolyl-peptide to produce 5-oxoproline and a peptide. The enzyme will not act on the 5-oxoprolyl peptide if the adjacent amino acid is l-proline. Enzyme activity is inhibited by thiol-blocking reagents. 

Initial sequencing attempts with HPLC-purified Acheta PDCF indicated a blocked amino-terminus. It was deblocked by pyroglutamyl amino peptidase and subjected to gas-phase sequencing. The resulting data, along with spectral analysis, indicated that the purified peptide has the sequence pGlu-Val-Asn-Phe-Ser-Thr-Gly-Trp-amide. This was also the deduced sequence for Gryllus AKH (43). The synthetic peptide. 

Proline iminopeptidase [L-Prolylpeptide hydrolase] (3.4.11.5) is produced. [Formerly EC3.4.1.4.] Pyroglutamyl aminopeptidase [L-Pyroglutamyl-peptide hydrolase, Pyrrolidone-carboxylate peptidase] (3.4.11.8) is produced. [Removes pyroglutamate from various penultimate amino acid residues except L-proline. Occurs in Pseudomonas, Bacillus subtilis, rat liver.]... 

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