title: Reduction of some Pt(IV) complexes with biologically important sulfur-donor ligands.
abstract: The reduction of the Pt(IV) complexes [PtCl4(bipy)], [PtCl4(dach)] and [PtCl4(en)] by glutathione (GSH), L-cysteine (L-Cys) and L-methionine (L-Met) was investigated by stopped-flow spectrophotometry at pH 2.0 (in 0.01 M perchloric acid) and at pH 7.2 (in 25 mM Hepes buffer). Kinetic measurements were performed under pseudo-first order conditions with an excess of the reducing agent. The order of the reactivity of the studied complexes was [PtCl4(bipy)] > [PtCl4(dach)] > [PtCl4(en)], and reactivity of investigated reducing agents followed the order GSH > L-Cys > L-Met. All the reactions between the selected Pt(IV) complexes and the sulfur donor biomolecules proceeded by a reductive elimination process that included nucleophilic attack by the reducing agent on one of the mutually trans-coordinated chloride ligands, which led to a two-electron transfer process. The final products of the redox reactions were the corresponding reduced Pt(II) complexes and the oxidized form of the reducing agents.
authors: Department of Chemistry, Faculty of Science, University of Kragujevac, R. Domanovića 12, P. O. Box 60, 34000 Kragujevac, Serbia.
authors: Snežana
authors: S
authors: Jovanović
authors: Biljana
authors: B
authors: Petrović
authors: Živadin D
authors: ŽD
authors: Bugarčić
authors: Rudi
authors: R
authors: van Eldik
mesh_terms: D002712:Chlorides / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008024:Ligands; D008715:Methionine / Q000737:chemistry; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013455:Sulfur / Q000737:chemistry*; D013997:Time Factors
chemical_list: D002712:Chlorides; D008024:Ligands; D009944:Organoplatinum Compounds; D010984:Platinum; D013455:Sulfur; D008715:Methionine; D005978:Glutathione; D003545:Cysteine; D010100:Oxygen