Enzymology
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.
