Enzymology
Acidity and nucleophilic reactivity of glutathione persulfide
Persulfides (RSSH/RSS−) participate in sulfur trafficking and metabolic processes, and are proposed to mediate the signaling effects of hydrogen sulfide (H2S). Despite their growing relevance, their chemical properties are poorly understood. Herein, we studied experimentally and computationally the formation, acidity, and nucleophilicity of glutathione persulfide (GSSH/GSS−), the derivative of the abundant cellular thiol glutathione (GSH). We characterized the kinetics and equilibrium of GSSH formation from glutathione disulfide and H2S.The Chemical Basis of Thiol Addition to Nitro-conjugated Linoleic Acid, a Protective Cell-signaling Lipid
Nitroalkene fatty acids are formed in vivo and exert protective and anti-inflammatory effects via reversible Michael addition to thiol-containing proteins in key signaling pathways. Nitro-conjugated linoleic acid (NO2-CLA) is preferentially formed, constitutes the most abundant nitrated fatty acid in humans, and contains two carbons that could potentially react with thiols, modulating signaling actions and levels. In this work, we examined the reactions of NO2-CLA with low molecular weight thiols (glutathione, cysteine, homocysteine, cysteinylglycine, and β-mercaptoethanol) and human serum albumin.Reaction of Hydrogen Sulfide with Disulfide and Sulfenic Acid to Form the Strongly Nucleophilic Persulfide
Background: Hydrogen sulfide (H2S) modulates physiological processes in mammals.Results: The reactivity of H2S toward disulfides (RSSR) and albumin sulfenic acid (RSOH) to form persulfides (RSSH) was assessed.Conclusion: H2S is less reactive than thiols. Persulfides have enhanced nucleophilicity.Significance: This kinetic study helps rationalize the contribution of the reactions with oxidized thiol derivatives to H2S biology.
