Protein thiols and disulfides (PSH/PSSP)

Protein thiols and disulfides represent the reduced and oxidized states of cysteine residues within the proteome, serving as critical regulators of protein structure, function, and cellular signaling. The reversible transition between the reduced thiol (-SH) and the oxidized disulfide (-S-S-) form acts as a molecular switch that responds to the cellular redox environment, influencing enzyme activity and protein-protein interactions (Giles et al., 2003). In many diseases, such as cancer and neurodegeneration, an imbalance in this redox state leads to oxidative stress and the formation of irreversible protein modifications like sulfinic or sulfonic acids (Circu & Aw, 2010). Pharmacological intervention often involves the use of thiol-containing compounds to scavenge reactive oxygen species or small molecules that covalently modify specific reactive cysteines to modulate protein function (Townsend et al., 2003). These targets are essential for maintaining cellular homeostasis and are exploited in treatments ranging from mucolytics to chemoprotective agents. Furthermore, the formation of disulfide bridges is vital for the stability of secreted proteins and the extracellular domains of cell-surface receptors.

Other names

Protein sulfhydrylsProtein-bound thiolsCysteine thiolsDisulfide bridgesProtein-S-glutathioneProtein-S-nitrosothiols

Thiol-disulfide exchange, reduction of oxidized protein cysteines, scavenging of reactive oxygen species, and covalent modification of reactive sulfhydryl groups.