title: Inactivation of pyroglutamyl aminopeptidase by N alpha-carbobenzoxy-L-pyroglutamyl chloromethyl ketone.
abstract: Pyroglutamyl aminopeptidase [pyrrolidone-carboxylate peptidase: EC 3.4.11.8] from Bacillus amyloliquefaciens was inactivated rapidly and irreversibly by N alpha-carbobenzoxy-L-pyroglutamyl chloromethyl ketone (Z-PGCK). The second-order rate constant of the inactivation was 1.1 x 10(5) M-1.s-1, a value which is comparable to that of the clostripain-TLCK reaction. The D-isomer of this chloromethyl ketone derivative was almost inert toward the enzyme under the same conditions. The inactivation reaction was prevented by the presence of a poor substrate, pyroglutamyl-valine. The PCMB-inactivated enzyme, that was reversibly reactivated by 2-mercaptoethanol, failed to react with Z-PGCK. These results suggest that this chloromethyl ketone derivative reacts as an affinity label, presumably with the active site cysteinyl residue of the enzyme, as was reported for L-pyroglutamyl chloromethyl ketone.
mesh_terms: D000345:Affinity Labels / Q000494:pharmacology; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D000626:Aminopeptidases / Q000037:antagonists & inhibitors*; D001407:Bacillus / Q000201:enzymology; D001665:Binding Sites; D002729:Chloromercuribenzoates / Q000494:pharmacology; D007700:Kinetics; D008623:Mercaptoethanol / Q000494:pharmacology; D011392:Proline / Q000031:analogs & derivatives / Q000494:pharmacology; D011751:Pyroglutamyl-Peptidase I / Q000037:antagonists & inhibitors*; D011761:Pyrrolidonecarboxylic Acid / Q000494:pharmacology / Q000031:analogs & derivatives; D020245:p-Chloromercuribenzoic Acid
chemical_list: D000345:Affinity Labels; D000590:Amino Acid Chloromethyl Ketones; D002729:Chloromercuribenzoates; C032441:N(alpha)-carbobenzoxypyroglutamic acid; D020245:p-Chloromercuribenzoic Acid; D008623:Mercaptoethanol; C032440:N-alpha-carbobenzoxypyroglutamic acid chloromethyl ketone; C029731:pyroglutamic acid chloromethyl ketone; D011392:Proline; D000626:Aminopeptidases; D011751:Pyroglutamyl-Peptidase I; D011761:Pyrrolidonecarboxylic Acid