Thiol group

The thiol group (also called sulfhydryl group or mercaptan, –SH) is a fundamental organic functional group in which a sulfur atom is bonded to a hydrogen atom[1][3][5][6]. Thiols are sulfur analogs of alcohols, with distinctive reactivity due to the larger, more nucleophilic sulfur atom[2][3]. Thiols are highly nucleophilic and play a central role in biological redox reactions, serving as reducing agents and forming disulfide bonds critical for protein structure and function (notably in cysteine residues)[3][6][7]. Thiol groups also act as key metal ion chelators and participate in various cellular signaling and enzymatic processes. While they are crucial for maintaining redox homeostasis and cellular defense (e.g., glutathione), their misregulation or covalent modification can contribute to disease mechanisms, particularly those involving oxidative stress and protein misfolding[3][7]. The thiol group itself is not considered a discrete therapeutic "target" like a receptor or enzyme, but rather a reactive functionality present in many biological molecules; thus, this entry is primarily chemical and not a standard pharmacological target[3][6]. Important caveat: The "thiol group" is a chemical functional group, not a specific protein, enzyme, receptor, or other canonical drug target. It appears as a moiety in many biomolecules (notably cysteine in proteins, glutathione, etc.), and is a site of action for many drugs and toxins, but is not itself a therapeutic target in the conventional sense[3][6][7]. Therefore, "is_target: false" and "is_incorrect: true" per your criteria.

Other names

sulfhydryl groupmercaptan group

Reducing agent; Nucleophilic substitution with electrophiles; Coordination to metal ions; Formation/breaking of disulfide bonds