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Updated: Aug 5, 2026

Spectrophotometric Screening for Potential Inhibitors of Cytosolic Glutathione S-Transferases
Published on: October 10, 2020
Direct spectroelectrochemical titration of glutathione
1Biotechnology Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899-8312, USA. vytas@nist.gov
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.
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