Stabilising cysteinyl thiol oxidation and nitrosation for proteomic analysis

•Disulphides, nitrosothiols and sulphenic acids are common, labile Cys modifications.•Thiol capping and stabilisation are essential for robust Cys analysis by MS.•Predicted Cys PTM formation should be considered alongside biological feasibility.

Oxidation and S-nitrosylation of cysteinyl thiols (Cys-SH) to sulfenic (Cys-SOH), sulfinic (Cys-SO2H), sulfonic acids (Cys-SO3H), disulphides and S-nitrosothiols are suggested as important post-translational modifications that can activate or deactivate the function of many proteins. Non-enzymatic post-translational modifications to cysteinyl thiols have been implicated in a wide variety of physiological and pathophysiological states but have been difficult to monitor in a physiological setting because of a lack of experimental tools.The purpose of this review is to bring together the approaches that have been developed for stably trapping cysteine either in its reduced or oxidised forms for enrichment and or subsequent mass spectrometric analysis. These tools are providing insight into potential targets for post-translational modifications to cysteine modification in vivo.This article is part of a Special Issue entitled: Special Issue: Posttranslational Protein modifications in biology and Medicine.

Graphical abstractAdduct formation with 5, 5-dimethy-1, 3-cyclohexadione (dimedone); the first chemical entity shown to trap sulphenic acids in proteins for detection.Figure optionsDownload full-size imageDownload high-quality image (60 K)Download as PowerPoint slide