title: Inactivation of peptidylglycine α-hydroxylating monooxygenase by cinnamic acid analogs.
abstract: Peptidylglycine α-amidating monooxygenase (PAM) is a bifunctional enzyme that catalyzes the final reaction in the maturation of α-amidated peptide hormones. Peptidylglycine α-hydroxylating monooxygenase (PHM) is the PAM domain responsible for the copper-, ascorbate- and O2-dependent hydroxylation of a glycine-extended peptide. Peptidylamidoglycolate lyase is the PAM domain responsible for the Zn(II)-dependent dealkylation of the α-hydroxyglycine-containing precursor to the final α-amidated peptide. We report herein that cinnamic acid and cinnamic acid analogs are inhibitors or inactivators of PHM. The inactivation chemistry exhibited by the cinnamates exhibits all the attributes of a suicide-substrate. However, we find no evidence for the formation of an irreversible linkage between cinnamate and PHM in the inactivated enzyme. Our data support the reversible formation of a Michael adduct between an active site nucleophile and cinnamate that leads to inactive enzyme. Our data are of significance given that cinnamates are found in foods, perfumes, cosmetics and pharmaceuticals.
authors.affiliation: a Department of Chemistry , Xavier University of Louisiana , New Orleans , LA , USA .
authors.forename: Neil R
authors.initials: NR
authors.lastname: McIntyre
authors.affiliation: a Department of Chemistry , Xavier University of Louisiana , New Orleans , LA , USA .
authors.forename: Edward W
authors.initials: EW
authors.lastname: Lowe
authors.affiliation: b Department of Chemistry , University of South Florida , Tampa , FL , USA , and.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Battistini
authors.affiliation: b Department of Chemistry , University of South Florida , Tampa , FL , USA , and.|c Florida Center for Drug Discovery and Innovation , Tampa , FL , USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Leahy
authors.affiliation: b Department of Chemistry , University of South Florida , Tampa , FL , USA , and.
authors.forename: David J
authors.initials: DJ
authors.lastname: Merkler
mesh_terms: D002934:Cinnamates / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015394:Molecular Structure; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D002934:Cinnamates; D004791:Enzyme Inhibitors; D009097:Multienzyme Complexes; C029010:cinnamic acid; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase
keywords: Cinnamate; cinnamate–Cu(I) complex; peptidylglycine α-hydroxylating monooxygenase; time-dependent enzyme inactivation