Co-ordinating properties of cyclopeptides. Thermodynamic and spectroscopic study on the formation of copper(II) complexes with cyclo(Gly-His)4 and cyclo(Gly-His-Gly)2 and their superoxide dismutase-like activity
Co-ordinating properties of cyclopeptides. Thermodynamic and spectroscopic study on the formation of copper(II) complexes with cyclo(Gly-His)4 and cyclo(Gly-His-Gly)2 and their superoxide dismutase-like activity(668 views) Bonomo RP, Impellizzeri G, Pappalardo G, Purrello R, Rizzarelli E, Tabbì G
Journal Of The Chemical Society Dalton Transactions (ISSN: 0300-9246), 1998; (22): 3851-3857.
Affiliations: Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
Istituto per lo Studio delle Sostanze Naturali di Interesse Alimentare e Chimico-Farmaceutico, Sezione per lo Studio di Modelli di Metallo-Enzimi, Viale A. Doria 6, 95125 Catania, Italy
References: Not available.
Co-ordinating properties of cyclopeptides. Thermodynamic and spectroscopic study on the formation of copper(II) complexes with cyclo(Gly-His)4 and cyclo(Gly-His-Gly)2 and their superoxide dismutase-like activity
Two cyclopeptides, cyclo(Gly-His)4 and cyclo(Gly-His-Gly)2 were synthesized with the specific aim to form copper(II) complexes which are able to mimic the active site of superoxide dismutase. Proton and copper(II) complexes were thermodynamically characterized. The copper(II) complexes were also studied by means of optical and ESR spectroscopy to gain information on their structural features and by voltammetry to know about their redox ability. Moreover, the antioxidant activity of these complex species was tested against enzymatically generated superoxide radical. Depending on the pH value of the solution, definite complexes could be characterized, in particular [Cu{cyclo(Gly-His)4}]2+ and [Cu{cyclo(Gly-His)4}H-2] and [Cu{cyclo(Gly-His-Gly)2}H-2] are the main species, which were taken into consideration to assay their antioxidant catalytic activity. The ESR studies suggested that a four-nitrogen co-ordination by means of imidazole nitrogen atoms or deprotonated peptide nitrogen atoms forms the environment around copper. At the same co-ordination level, the redox properties of these compounds parallel their scavenging abilities against O2 - which are lower than those of other copper(II) complexes previously tested. The [Cu{cyclo(Gly-His)4}]2+ complex showed higher redox potential and better catalytic ability than [Cu{cyclo(Gly-His)4}H-2] and [Cu{cyclo(Gly-His-Gly)2}H-2], which have roughly similar redox potentials and scavenging abilities.
Co-ordinating properties of cyclopeptides. Thermodynamic and spectroscopic study on the formation of copper(II) complexes with cyclo(Gly-His)4 and cyclo(Gly-His-Gly)2 and their superoxide dismutase-like activity
Co-ordinating properties of cyclopeptides. Thermodynamic and spectroscopic study on the formation of copper(II) complexes with cyclo(Gly-His)4 and cyclo(Gly-His-Gly)2 and their superoxide dismutase-like activity
Kállay C, Dávid A, Timári S, Nagy EM, Sanna D, Garribba E, Micera G, De Bona P, Pappalardo G, Rizzarelli E, Sóvágó I * Copper(II) complexes of rat amylin fragments(779 views) Dalton T (ISSN: 1477-9234, 1477-9226, 1477-9234electronic), 2011 Oct 14; 40(38): 9711-9721. Impact Factor:3.838 ViewExport to BibTeXExport to EndNote