title: Surface plasmon resonance analysis of the binding mechanism of pharmacological and peptidic inhibitors to human somatic angiotensin I-converting enzyme.
abstract: Somatic angiotensin I-converting enzyme (ACE) possesses two catalytic domains and plays a major role in the regulation of blood pressure, thus representing a therapeutic target for the treatment of hypertension. We present a comprehensive surface plasmon resonance (SPR) study of the interaction of human somatic ACE with the pharmacological inhibitors captopril and lisinopril, the bradykinin potentiating peptide BPP-11b, and the food peptidic inhibitors from bovine αs2-casein, F(174)ALPQYLK(181) and F(174)ALPQY(179). SPR binding curves recorded with the high potency inhibitors captopril, lisinopril, and BPP-11b were evaluated both by regression analysis and by kinetic distribution analysis. The results indicated that captopril and lisinopril bound ACE with two K(D)'s differing by a factor 10-20 and >30, respectively (lowest K(D) = 0.1-0.3 nM for both inhibitors). This shows, for the first time in a direct binding assay with the two-domain enzyme, the existence of two binding modes of the pharmacological inhibitors, presumably with the two ACE domains. The BPP-11b-ACE binding curves were complex but showed a predominant interaction with K(D) in the nanomolar range. The caseinopeptides, known to inhibit ACE with an IC₅₀ of 4.3 μM, bound to ACE with K(D) = 3-4 μM. Mapping of the F(174)ALPQY(179) binding site on ACE by sequential binding studies using captopril or BPP-11b indicated that it bound to (or near) the two active sites of ACE, in agreement with the stoichiometry of 2 determined from data fitting. Our results provide a detailed characterization of ACE-inhibitor binding modes and validate SPR for predicting the inhibitory potential of new compounds.
authors.affiliation: Université de Lorraine , Unité de Recherche Animal et Fonctionnalités des Produits Animaux (UR AFPA), Équipe Protéolyse et Biofonctionnalités des Protéines et des Peptides (PB2P), Faculté des Sciences et Technologies, Campus Aiguillettes, BP 70239, Vandœuvre-lès-Nancy F-54506, France.
authors.forename: Faïza
authors.initials: F
authors.lastname: Zidane
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Zeder-Lutz
authors.forename: Danièle
authors.initials: D
authors.lastname: Altschuh
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Girardet
authors.forename: Laurent
authors.initials: L
authors.lastname: Miclo
authors.forename: Catherine
authors.initials: C
authors.lastname: Corbier
authors.forename: Céline
authors.initials: C
authors.lastname: Cakir-Kiefer
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry*; D000818:Animals; D016466:CHO Cells; D002216:Captopril / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D017706:Lisinopril / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry; D007703:Peptidyl-Dipeptidase A / Q000737:chemistry*; D011485:Protein Binding / Q000187:drug effects; D025941:Protein Interaction Mapping; D020349:Surface Plasmon Resonance
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004800:Enzymes, Immobilized; D009842:Oligopeptides; D002216:Captopril; D017706:Lisinopril; D007703:Peptidyl-Dipeptidase A