title: Superoxide scavenging by thiol/copper complex of captopril--an EPR spectroscopy study.
abstract: Scavenging of superoxide radical by angiotensin converting enzyme (ACE) inhibitor captopril (CAP), a thiol compound, was studied by several investigators and the results were contradictory; while some reported a high superoxide scavenging activity of CAP others found that CAP removed superoxide inefficiently. In this work we show that in the presence of copper ions the apparent rate of superoxide removal by CAP (molar ratio CAP:CuSO4 4:1) was two orders of magnitude higher (approximately 1.5 x 10(5) M-1s-1 at pH 7.4) than the literature value for superoxide scavenging by CAP alone (< 10(3) M-1s-1 at pH 7.4). We presume that in the presence of copper ions a CAP/copper complex with a SOD-mimicking activity is being formed. Similar results were also obtained with another thiol glutathione (GSH). The possible role of the CAP/copper complexes in the anti-inflammatory effect of CAP is discussed.
authors.affiliation: Department of Physical Chemistry, Faculty of Chemical Technology, Slovak Technical University, Bratislava.
authors.forename: J
authors.initials: J
authors.lastname: Reguli
authors.forename: V
authors.initials: V
authors.lastname: Misík
mesh_terms: D002216:Captopril / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D019327:Copper Sulfate; D003497:Cyclic N-Oxides; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000737:chemistry*; D005978:Glutathione / Q000737:chemistry; D010084:Oxidation-Reduction; D013113:Spin Labels; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013481:Superoxides / Q000737:chemistry*
chemical_list: D003497:Cyclic N-Oxides; D016166:Free Radical Scavengers; D013113:Spin Labels; D013438:Sulfhydryl Compounds; D013481:Superoxides; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D003300:Copper; D002216:Captopril; D005978:Glutathione; D019327:Copper Sulfate; D004121:Dimethyl Sulfoxide