Cellular protein sulfhydryl systems (multiple cysteine-containing proteins)

Cellular protein sulfhydryl systems, comprising a diverse array of multiple cysteine-containing proteins, represent a critical pharmacological and toxicological target (DrugBank DB00954; T3DB T3D0011). Cysteine residues, with their reactive thiol (-SH) groups, are essential for the catalytic activity of many enzymes, the structural stability of proteins via disulfide bonds, and the maintenance of cellular redox homeostasis (PubMed: 21953168). Heavy metals such as mercury, arsenic, and lead exhibit a high affinity for these sulfhydryl groups, forming stable covalent mercaptides that can lead to protein denaturation and enzyme inhibition. This interaction is the primary mechanism underlying the systemic toxicity of heavy metal poisoning. Additionally, certain therapeutic agents like cisplatin and ethacrynic acid target these systems to exert their effects, while chelating agents like dimercaprol are used to protect these cellular thiols by sequestering toxic metals. The bioactivation of drugs like nitroglycerin also depends on the availability of these cellular sulfhydryl groups (PubMed: 17606654). The integrity of these sulfhydryl systems is vital for cellular survival, and their disruption is a hallmark of oxidative stress and various metabolic disorders.

Other names

Protein thiolsSulfhydryl groupsCellular thiol poolProtein sulfhydrylsCysteine-rich proteinsProtein sulfhydryl systems

Covalent binding of electrophilic agents or heavy metal ions to the sulfur atom of cysteine residues (thiol/sulfhydryl groups), leading to protein denaturation, enzyme inactivation, or disruption of redox signaling.