The fraction of sulfur existing as free sulfhydryl moieties (RSH) in eukaryotic cells largely resides in the low-molecular-weight compounds glutathione, cysteine, and homocysteine.' Although these compounds exploit unique aspecta of sulfur chemistry to execute various thiol-specific biochemical functions, they share many physical properties and a common chemistry. Indeed, the conversion of reduced thiols to S-nitroso thiols (thionitrites, RSNO) ...
