Related Experiment Video
Updated: Aug 17, 2026

Profiling Thiol Redox Proteome Using Isotope Tagging Mass Spectrometry
Published on: March 24, 2012
Quantitative determination and reversible modification of thiols using imidazolidine biradical disulfide label
V V Khramtsov1, V I Yelinova, Glazachev YuI
1Institute of Chemical Kinetics and Combustion, Novosibirsk, Russia. khramts@ns.kinetics.nsc.ru
Abstract:
Earlier we reported an ESR method of quantitative determination of sulfhydryl groups. The method is based on the application of the imidazoline biradical disulfide label, R1S-SR1, which participates in the reaction of thiol-disulfide exchange followed by dramatic changes in ESR spectra. One of the disadvantages of the application of R1S-SR1 at physiological conditions is the requirement of excess of the biradical compared with thiol content which results in the consumption of the thiols and irreversible damage of the system under study. In the present paper we propose imidazolidine biradical disulfide reagent, R2S-SR2, for ESR determination of thiols and provide an experimental basis for its application. This label has the advantages of the previously used biradical disulfide, R1S-SR1, such as high sensitivity down to 1 microM of thiols even in opaque samples and could possibly be used for reversible modification of proteins and enzymes. The particular properties of the R2S-SR2 are pH-sensitivity of its ESR spectrum, higher stability of the imidazolidine radical fragment towards biological reductants and low concentration of the label sufficient for thiol determination at physiological conditions. The latter makes it possible to use ESR spectroscopy for non-invasive thiol measurements in biological systems, in vivo applications included.
More Related Videos
08:47Synthesis and Bioconjugation of Thiol-Reactive Reagents for the Creation of Site-Selectively Modified Immunoconjugates
Published on: March 6, 2019
07:16Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
Related Concept Videos
Structure and Nomenclature of Thiols and Sulfides
Preparation and Reactions of Thiols
Preparation and Reactions of Sulfides
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
Redox Titration: Overview
Redox Titration: Iodimetry and Iodometry