Vicinal dithiol and reduced cysteine residues in cellular proteins (VDT/Cys-SH)

Vicinal dithiols and reduced cysteine residues are critical functional groups within cellular proteins that serve as primary targets for both endogenous redox signaling and exogenous toxins. These groups consist of sulfhydryl (-SH) moieties, which, when located in close proximity (vicinal), are particularly sensitive to oxidation and heavy metal binding. They play essential roles in the catalytic activity of various enzymes, such as the pyruvate dehydrogenase complex, and are involved in maintaining the cellular redox environment. In the context of toxicology, heavy metals like arsenic and mercury exert their poisonous effects by binding to these dithiol groups, thereby inactivating vital metabolic pathways. Therapeutic strategies often involve the use of chelating agents, such as dimercaprol or succimer, which possess competing thiol groups that can sequester the metals and restore protein function. Additionally, these residues are targets for electrophilic drugs and are central to the mechanism of action of certain chemotherapeutic agents and redox-modulating therapies.

Other names

Protein sulfhydryl groupsProtein thiolsVicinal dithiolsReduced cysteinyl residuesProtein-bound thiols

Chelation of heavy metals to prevent or reverse binding to endogenous protein thiols; covalent modification by electrophiles; redox modulation through thiol-disulfide exchange.