Related Experiment Video
Updated: Jul 9, 2026

Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
Mechanism of thiol oxidation by the superoxide radical
Bruno Cardey1, Sarah Foley, Mironel Enescu
1University of Franche-Comte, Laboratoire de Microanalyses Nucleaires, UMR CEA E4, 16 route de Gray, 25030 Besancon, France.
Abstract:
In spite of the large quantity of experimental work that deals with the oxidation of thiols by superoxide, the mechanism of this reaction is still controversial. The ab initio molecular orbital calculations reported here predict that the main reaction pathway includes the formation of a three-electron-bonded adduct followed by the elimination of the hydroxide anion, giving the sulfinyl radical as the reaction product. The alternative reaction pathway consisting of hydrogen atom transfer from the thiol to the protonated superoxide radical involves a reaction energy barrier that is significantly higher. The difference between the two reaction energy barriers is clearly beyond the expected computational uncertainty. The systematic scanning of the potential energy surface reveals no other competitive reaction pathways. The present results provide a useful basis for the interpretation of the complex experimental data related to thiol oxidation by superoxide radical in a biological environment.
Related Concept Videos
Preparation and Reactions of Thiols
Radical Autoxidation
Oxidation of Alcohols
The process of oxidation in a chemical reaction is observed in any of the three forms:
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Preparation and Reactions of Sulfides
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids

