Hypochlorous acid (HOCL) oxidizes Cys residues to form Cys-sulfenyl chloride

Stable Identifier
Reaction [transition]
Homo sapiens
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Hypochlorous acid (HOCl) is a powerful oxidant generated from H2O2 and Cl- by the heme enzyme myeloperoxidase (MPO), which is released from activated leukocytes. HOCl leads to chlorination of thiol-containing cysteine (Cys) residues forming Cys-sulfenyl chloride (Cys-SCl) intermediate and then Cys-sulfenic acid (Cys-SOH), which can either form a disulfide with an adjacent thiol or be further oxidized by HOCl to generate Cys- sulfinic and Cys-sulfonic acids sequentially (Peskin AV & Winterbourn CC 2001; Hawkins CL et al. 2003; Paulsen CE & Carroll KS 2013; Winterbourn CC & Kettle AJ 2013). Disulfides function as redox switches to control protein activity and protect thiol groups against overoxidation to Cys-sulfinic and -sulfonic acids.

Literature References
PubMed ID Title Journal Year
22881869 Redox reactions and microbial killing in the neutrophil phagosome

Kettle, AJ, Winterbourn, CC

Antioxid. Redox Signal. 2013
14661089 Hypochlorite-induced oxidation of amino acids, peptides and proteins

Davies, MJ, Pattison, DI, Hawkins, CL

Amino Acids 2003
11182528 Kinetics of the reactions of hypochlorous acid and amino acid chloramines with thiols, methionine, and ascorbate

Peskin, AV, Winterbourn, CC

Free Radic. Biol. Med. 2001
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