Acidity of persulfides and its modulation by the protein environments in sulfide quinone oxidoreductase and thiosulfate sulfurtransferase

Benchoam, Dayana; Cuevasanta, Ernesto; Roman, Joseph V.; Banerjee, Ruma; Alvarez, Beatriz

doi:10.1016/j.jbc.2024.107149

Cited by 3 publications

(1 citation statement)

References 62 publications

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“…In contrast, the monosulfide 5b-S – lacks resonance stabilization and is more basic (a worse leaving group) than disulfide 5b-S 2 – , itself more basic than the longer polysulfides 5b-S x – . The measured p K a values of inorganic polysulfides in water (H 2 S: 7.0, H 2 S 2 : 5.1, H 2 S 3 : 4.3, H 2 S 4 –H 2 S 8 : 3.9–3.4) − and the increased acidity of alkyl persulfides (RSSH) versus their corresponding thiols (by 1–4 p K a units) − match this conclusion. Overall, unimolecular cyclization is kinetically plausible mostly for long polysulfides but does not provide a clear thermodynamic driving force toward the formation of the monosulfide that is needed for 2-aminothiophene formation.…”

Section: Resultssupporting

confidence: 74%

Mechanisms of the Gewald Synthesis of 2-Aminothiophenes from Elemental Sulfur

Sharma,

Champagne

2024

J. Org. Chem.

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Section: Resultssupporting

confidence: 74%

Mechanisms of the Gewald Synthesis of 2-Aminothiophenes from Elemental Sulfur

Sharma,

Champagne

2024

J. Org. Chem.

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Reaction of peroxynitrite with thiols, hydrogen sulfide and persulfides

Trujillo,

Cuevasanta,

Turell

et al. 2024

Redox Biochemistry and Chemistry

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The SOD1 Inhibitor, LCS-1, Oxidizes H2S to Reactive Sulfur Species, Directly and Indirectly, through Conversion of SOD1 to an Oxidase

Olson,

Takata,

Clear

et al. 2024

Antioxidants

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LCS-1, a putative selective inhibitor of SOD1, is a substituted pyridazinone with rudimentary similarity to quinones and naphthoquinones. As quinones catalytically oxidize H2S to biologically active reactive sulfur species (RSS), we hypothesized LCS-1 might have similar attributes. Here, we examine LCS-1 reactions with H2S and SOD1 using thiol-specific fluorophores, liquid chromatography–mass spectrometry, electron paramagnetic resonance (EPR), UV–vis spectrometry, and oxygen consumption. We show that LCS-1 catalytically oxidizes H2S in buffer solutions to form RSS, namely per- and polyhydrosulfides (H2Sn, n = 2–6). These reactions consume oxygen and produce hydrogen peroxide, but they do not have an EPR signature, nor do they affect the UV–vis spectrum. Surprisingly, LCS-1 synergizes with SOD1, but not SOD2, to oxidize H2S to H2S3-6. LCS-1 forms monothiol adducts with H2S, glutathione (GSH), and cysteine (Cys), but not with oxidized glutathione or cystine; both thiol adducts inhibit LCS-1-SOD1 synergism. We propose that LCS-1 forms an adduct with SOD1 that disrupts the intramolecular Cys57-Cys146 disulfide bond and transforms SOD1 from a dismutase to an oxidase. This would increase cellular ROS and polysulfides, the latter potentially affecting cellular signaling and/or cytoprotection.

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Acidity of persulfides and its modulation by the protein environments in sulfide quinone oxidoreductase and thiosulfate sulfurtransferase

Cited by 3 publications

References 62 publications

Mechanisms of the Gewald Synthesis of 2-Aminothiophenes from Elemental Sulfur

Mechanisms of the Gewald Synthesis of 2-Aminothiophenes from Elemental Sulfur

Reaction of peroxynitrite with thiols, hydrogen sulfide and persulfides

The SOD1 Inhibitor, LCS-1, Oxidizes H2S to Reactive Sulfur Species, Directly and Indirectly, through Conversion of SOD1 to an Oxidase

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