Low-molecular-weight S-nitrosothiols

This chapter is primarily concerned with the S-nitrosothiols of low molecular weight. S-nitrosothiols (thionitrites, RSNO) appear as endogenous reaction products of NO or NO metabolites with sulfhydryl groups. Prime targets are the sulfhydryl groups on cysteine residues found in many different proteins or the thiol moieties on endogenous glutathione (GSH) or cysteine (Cys). The nitrosation of the sulfhydryl moiety leads to S-nitrosothiols with high and low molecular weight, respectively. The interest in the S-nitrosothiols was motivated by the observation that these compounds form in vivo and may elicit physiological responses that are strongly reminiscent of free NO radicals. Well-documented examples are vasodilation and the inhibition of platelet aggregation.