Reactive Sulfur Species: Kinetics and Mechanism of the Hydrolysis of Cysteine Thiosulfinate Ester

Ashby, Michael T.

doi:10.1021/tx700168z

Cited by 37 publications

(34 citation statements)

References 61 publications

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“…Indeed, model thiosulfinate compounds have been shown to be sensitive to hydrolysis at neutral or basic pH. Although the mechanism of thiosulfinate hydrolysis appears more complex than nucleophilic attack by thiols, it would significantly involve release of reduced Srx and PrxSO 2 as an initial step (28,29). This result again supports the thiosulfinate nature of the 37,262-Da species.…”

Section: S-sprx) Disulfide Bondsmentioning

confidence: 67%

“…Due to the instability of thiosulfinate bonds at near neutral pH, no tryptic peptide containing a thiosulfinate crosslink was detected by nanoLC-MS/MS. To attempt to directly characterize the putative thiosulfinate intermediate, pepsin digestions were performed at acidic pH, which is expected to stabilize the thiosulfinate bond (28). Despite accurate mass measurement of pepsic peptides, no peptide containing either the disulfide or the thiosulfinate bond could be unambiguously sequenced even if molecular masses that could correspond to such peptides were measured with a high accuracy.…”

Section: S-sprx) Disulfide Bondsmentioning

confidence: 99%

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Evidence for the Formation of a Covalent Thiosulfinate Intermediate with Peroxiredoxin in the Catalytic Mechanism of Sulfiredoxin

Roussel

Béchade

Kriznik

et al. 2008

Journal of Biological Chemistry

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The typical 2-Cys peroxiredoxins are thiol-peroxidases involved in the physiology of hydrogen peroxide not only as a toxic but also as a signaling molecule. Coordination of these functions depends on the sulfinylation of the catalytic Cys, a modification reversed by ATP-dependent sulfiredoxin, which specifically reduces the sulfinic acid group of overoxidized 2-Cys peroxiredoxins into a sulfenic acid. Sulfiredoxin was originally proposed to operate by covalent catalysis, with formation of a peroxiredoxin-sulfiredoxin intermediate linked by a thiosulfinate bond between the catalytic Cys of both partners, a hypothesis rejected by a study of the human enzyme. To settle the argument, we investigated the catalytic mechanism of Saccharomyces cerevisiae sulfiredoxin, by the characterization of the nature and kinetics of formation of the protein species formed between sulfiredoxin and its substrate in the presence of ATP, using mutants of the non-essential Cys residues of both proteins. We observed the formation of a dithiothreitol-reducible peroxiredoxin-sulfiredoxin species using SDS-PAGE and Western blot analysis, and its mass was shown to correspond to a thiosulfinate complex by high resolution mass spectrometry coupled to liquid chromatography. We next measured indirectly and directly a rate constant of formation of the thiosulfinate species of ϳ2 min ؊1 , for both wild-type and mutant sulfiredoxins, at least equal to the steady-state rate constant of the reaction, with a stoichiometry of 1:1 relative to peroxiredoxin. Taken altogether, our results strongly argue in favor of the formation of a covalent thiosulfinate peroxiredoxin-sulfiredoxin species as an intermediate on the catalytic pathway.

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Section: S-sprx) Disulfide Bondsmentioning

confidence: 67%

Section: S-sprx) Disulfide Bondsmentioning

confidence: 99%

Evidence for the Formation of a Covalent Thiosulfinate Intermediate with Peroxiredoxin in the Catalytic Mechanism of Sulfiredoxin

Roussel

Béchade

Kriznik

et al. 2008

Journal of Biological Chemistry

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“…In some cases the situation can be more complicated and depending on the mechanism and conditions the proportionality constant can be even larger (73). In these cases a more comprehensive kinetic analysis is required to establish the concentration dependencies of the rate equation.…”

Section: The Rate Equation and Rate Determining Concentrationsmentioning

confidence: 99%

Kinetics and Mechanisms of Thiol–Disulfide Exchange Covering Direct Substitution and Thiol Oxidation-Mediated Pathways

Nagy

2013

Antioxidants & Redox Signaling

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364

310

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Kinetic studies of proteins are more challenging than small molecules, and quite often investigators are forced to sacrifice the rigor of the experimental approach to obtain the important kinetic and mechanistic information. However, recent technological advances allow a more comprehensive analysis of enzymatic systems via using the systematic kinetics apparatus that was developed for small molecule reactions, which is expected to provide further insight into the cell's machinery.

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“…It is therefore rather amazing—and in many ways very fortunate—that the field of inorganic RSS over the years has developed its own dynamic, fuelled by three parallel developments: (a) the stream of ten prominent publications on inorganic RSS by Michael Ashby and his colleagues between 2004 and 2010, all with a title commencing with “Reactive Sulfur Species” and focussed on inorganic RSS [46,72,73,74,75,76,77,78,79,80,81], (b) The eruption of H 2 S research, accompanied by the suspicion that H 2 S is probably not really the signalling molecule one had previously thought, but that there is a case of mistaken identity, involving an entire series of inorganic polysulfides (H 2 S x ), which clearly belong to the realm of inorganic RSS, (c) the issue of the lost electron, i.e., the rather curious situation that many interactions involving thiols and radicals, for instance in the field of S-nitrosothiols, do not add up when it comes to electrons, hence questioning if RSS are really predominantly electrophilic compounds, such as sulfenic acids, or rather radical species. We will now consider the inorganic side of sulfide species in more detail.…”

Section: What Are Rss?mentioning

confidence: 99%

“…The research by Michael Ashby and his colleagues at the time was concerned with rather exotic inorganic molecules such as hypothiocyanite (HOSCN), which is chemically similar to hypochlorous acid (HOCl) and, similar to HOCl and many ROS, is used as part of the body’s inorganic defence force [46,73,74,78]. Taking a more physico-chemical approach, and often focussing on kinetics, these studies were able to identify a range of reactive species, biologically relevant reactions and reaction products related to the concept of (inorganic) RSS.…”

Section: What Are Rss?mentioning

confidence: 99%

The Reactive Sulfur Species Concept: 15 Years On

et al. 2017

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Fifteen years ago, in 2001, the concept of “Reactive Sulfur Species” or RSS was advocated as a working hypothesis. Since then various organic as well as inorganic RSS have attracted considerable interest and stimulated many new and often unexpected avenues in research and product development. During this time, it has become apparent that molecules with sulfur-containing functional groups are not just the passive “victims” of oxidative stress or simple conveyors of signals in cells, but can also be stressors in their own right, with pivotal roles in cellular function and homeostasis. Many “exotic” sulfur-based compounds, often of natural origin, have entered the fray in the context of nutrition, ageing, chemoprevention and therapy. In parallel, the field of inorganic RSS has come to the forefront of research, with short-lived yet metabolically important intermediates, such as various sulfur-nitrogen species and polysulfides (Sx2−), playing important roles. Between 2003 and 2005 several breath-taking discoveries emerged characterising unusual sulfur redox states in biology, and since then the truly unique role of sulfur-dependent redox systems has become apparent. Following these discoveries, over the last decade a “hunt” and, more recently, mining for such modifications has begun—and still continues—often in conjunction with new, innovative and complex labelling and analytical methods to capture the (entire) sulfur “redoxome”. A key distinction for RSS is that, unlike oxygen or nitrogen, sulfur not only forms a plethora of specific reactive species, but sulfur also targets itself, as sulfur containing molecules, i.e., peptides, proteins and enzymes, preferentially react with RSS. Not surprisingly, today this sulfur-centred redox signalling and control inside the living cell is a burning issue, which has moved on from the predominantly thiol/disulfide biochemistry of the past to a complex labyrinth of interacting signalling and control pathways which involve various sulfur oxidation states, sulfur species and reactions. RSS are omnipresent and, in some instances, are even considered as the true bearers of redox control, perhaps being more important than the Reactive Oxygen Species (ROS) or Reactive Nitrogen Species (RNS) which for decades have dominated the redox field. In other(s) words, in 2017, sulfur redox is “on the rise”, and the idea of RSS resonates throughout the Life Sciences. Still, the RSS story isn’t over yet. Many RSS are at the heart of “mistaken identities” which urgently require clarification and may even provide the foundations for further scientific revolutions in the years to come. In light of these developments, it is therefore the perfect time to revisit the original hypotheses, to select highlights in the field and to question and eventually update our concept of “Reactive Sulfur Species”.

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Reactive Sulfur Species: Kinetics and Mechanism of the Hydrolysis of Cysteine Thiosulfinate Ester

Cited by 37 publications

References 61 publications

Evidence for the Formation of a Covalent Thiosulfinate Intermediate with Peroxiredoxin in the Catalytic Mechanism of Sulfiredoxin

Evidence for the Formation of a Covalent Thiosulfinate Intermediate with Peroxiredoxin in the Catalytic Mechanism of Sulfiredoxin

Kinetics and Mechanisms of Thiol–Disulfide Exchange Covering Direct Substitution and Thiol Oxidation-Mediated Pathways

The Reactive Sulfur Species Concept: 15 Years On

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