title: Direct spectroelectrochemical titration of glutathione.
abstract: Previous potentiometric attempts to determine the formal potential (E'(0)) of key intracellular redox buffer glutathione resulted in contradictory values. We have developed a spectroelectrochemical method using direct reduction on metal oxide electrodes. Disulfide absorbance at 258 nm was used to titrate glutathione in the thin layer cell reversibly. At conditions close to physiological ([GSH] = 0.001-0.005 mol/l, pH = 7.34; I = 0.1 mol/l; T = 298.15 K), we have measured glutathione E(0)' = -0.22 +/- 0.02 V (NHE), corroborating the results of equilibrium measurements.
authors.affiliation: Biotechnology Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899-8312, USA. vytas@nist.gov
authors.forename: Vytas
authors.initials: V
authors.lastname: Reipa
mesh_terms: D004563:Electrochemistry; D004566:Electrodes; D005978:Glutathione / Q000032:analysis / Q000737:chemistry*; D010084:Oxidation-Reduction; D013057:Spectrum Analysis; D017186:Titrimetry
chemical_list: D005978:Glutathione