title: Cyclic voltammetric study of the redox system of glutathione using the disulfide bond reductant tris(2-carboxyethyl)phosphine.
abstract: The stabilization of the reduction state of proteins and peptides is very important for the monitoring of protein-protein, protein-DNA and protein-xenobiotic interactions. The reductive state of protein or peptide is characterized by the reactive sulfhydryl group. Glutathione in the reduced (GSH) and oxidized (GSSG) forms was studied by cyclic voltammetry. Tris(2-carboxyethyl)phosphine (TCEP) as the disulfide bond reductant and/or hydrogen peroxide as the sulfhydryl group oxidant were used. Cyclic voltammetry measurements, following the redox state of glutathione, were performed on a hanging mercury drop electrode (HMDE) in borate buffer (pH 9.2). It was shown that in aqueous solutions TCEP was able to reduce disulfide groups smoothly and quantitatively. The TCEP response at -0.25 V vs. Ag/AgCl/3 M KCl did not disturb the signals of the thiol/disulfide redox couple. The origin of cathodic and anodic signals of GSH (at -0.44 and -0.37 V) and GSSG (at -0.69 and -0.40 V) glutathione forms is discussed. It was shown that the application of TCEP to the conservation of sulfhydryl groups in peptides and proteins can be useful instrument for the study of peptides and proteins redox behavior.
authors.affiliation: Department of Chemistry and Biochemitry, Faculty of Agronomy, Mendel University of Agriculture and Forestry, Brno, Czech Republic.
authors.forename: René
authors.initials: R
authors.lastname: Kizek
authors.forename: Jan
authors.initials: J
authors.lastname: Vacek
authors.forename: Libuse
authors.initials: L
authors.lastname: Trnková
authors.forename: Frantisek
authors.initials: F
authors.lastname: Jelen
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D004220:Disulfides / Q000032:analysis / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D005978:Glutathione / Q000032:analysis / Q000737:chemistry*; D019803:Glutathione Disulfide / Q000032:analysis / Q000737:chemistry; D008422:Materials Testing / Q000379:methods*; D010084:Oxidation-Reduction; D010720:Phosphines / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D004220:Disulfides; D005978:Glutathione; D019803:Glutathione Disulfide; D010720:Phosphines; C080938:tris(2-carboxyethyl)phosphine