title: Rapid reaction of hydrogen sulfide with the neutrophil oxidant hypochlorous acid to generate polysulfides.
abstract: H₂S has been recognized as a signaling molecule and mediator of inflammation. Here, we report the kinetics and mechanism of its reaction with the neutrophil oxidant hypochlorous acid. Stopped flow studies, carried out at high pH, showed this reaction to be extremely fast, with a second-order rate constant extrapolated to be 2 × 10⁹ M⁻¹ s⁻¹ at pH 7.4. The reaction produces polysulfides rather than polythionates and may represent a novel pathway for protein Cys-sulfhydration, a recently proposed mechanism for H₂S signaling.
authors.affiliation: Department of Pathology, University of Otago Christchurch, P.O. Box 4345, Christchurch, New Zealand. peter.nagy@otago.ac.nz
authors.forename: Péter
authors.initials: P
authors.lastname: Nagy
authors.forename: Christine C
authors.initials: CC
authors.lastname: Winterbourn
mesh_terms: D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006997:Hypochlorous Acid / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D009504:Neutrophils / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D011506:Proteins / Q000378:metabolism; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011506:Proteins; D013440:Sulfides; D006997:Hypochlorous Acid; C032915:polysulfide; D003545:Cysteine; D006862:Hydrogen Sulfide