Details

Autor(en) / Beteiligte

• Bischoff, Eileen
• Lang, Lukas
• Zimmermann, Jannik
• Luczak, Maximilian
• Kiefer, Anna Maria
• Niedner-Schatteburg, Gereon
• Manolikakes, Georg
• Morgan, Bruce
• Deponte, Marcel

Titel

Glutathione kinetically outcompetes reactions between dimedone and a cyclic sulfenamide or physiological sulfenic acids

Ist Teil von

• Free radical biology & medicine, 2023-11, Vol.208, p.165-177

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Dimedone and its derivates are used as selective probes for the nucleophilic detection of sulfenic acids in biological samples. Qualitative analyses suggested that dimedone also reacts with cyclic sulfenamides. Furthermore, under physiological conditions, dimedone must compete with the highly concentrated nucleophile glutathione. We therefore quantified the reaction kinetics for a cyclic sulfenamide model peptide and the sulfenic acids of glutathione and a model peroxiredoxin in the presence or absence of dimedone and glutathione. We show that the cyclic sulfenamide is stabilized at lower pH and that it reacts with dimedone. While reactions between dimedone and sulfenic acids or the cyclic sulfenamide have similar rate constants, glutathione kinetically outcompetes dimedone as a nucleophile by several orders of magnitude. Our comparative in vitro and intracellular analyses challenge the selectivity of dimedone. Consequently, the dimedone labeling of cysteinyl residues inside living cells points towards unidentified reaction pathways or unknown, kinetically competitive redox species. Sulfenic acids in biological samples are indirectly detected by nucleophilic probes. Whether dimedone probes also detect cyclic sulfenamides is controversial and depends on kinetic competitions. Furthermore, dimedone probes have to compete with the highly abundant physiological nucleophile glutathione (GSH). Kinetic assays in vitro and in yeast challenge the specificity of dimedone and highlight the benefits of GSH competition assays. [Display omitted] •Glutathione kinetically outcompetes dimedone as a nucleophile.•Dimedone cannot discriminate between peptide sulfenic acids and cyclic sulfenamides.•The presence and detectability of cyclic sulfenamides could be highly pH-dependent.•Origin and relevance of dimedone-labeled peptides often remain to be analyzed.•Glutathione competition assays are recommended for nucleophilic probe development.