The reactivity of dinitrogen trioxide and of nitrosyl thiocyanate

Doherty, Anne M. M.; Garley, Michael S.; Howes, Kevin R.; Stedman, Geoffrey

doi:10.1039/p29860000143

Cited by 8 publications

(5 citation statements)

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“…Therefore, we have chosen for k 15a the average value of (1.0 ± 0.6) × 10 9 M -1 s -1 , and hence k 15b < 1.0 × 10 5 M -1 s -1 . These results are in agreement with the literature data, which demonstrate that N 2 O 3 (an electrophilic agent) nitrosates the free base form of the substrate (a nucleophilic agent) with rate constants that vary between 1.4 × 10 7 and 5.9 × 10 9 M -1 s -1 . ,− …”

Section: Discussionsupporting

confidence: 92%

“…The recent value (3.03 ± 0.23) × 10 -3 M -1 , is in agreement with the value calculated thermodynamically, (2.3 ± 1.0) × 10 -3 M -1 . The rate constant of reaction −7 has been determined in several systems to be 9−13.9 M -1 s -1 at 25 °C. ,, As these measurements were carried out in acid solutions, k 7a = 2970−4590 s -1 , which are higher than those determined directly. , We have no explanation for this discrepancy. We can only argue that our data is more consistent with k 7a > 2 × 10 3 s -1 and that Gratzel's value is too low.…”

Section: Discussionsupporting

confidence: 83%

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Formation of Peroxynitrite from the Nitrosation of Hydrogen Peroxide by an Oxygenated Nitric Oxide Solution

Goldstein

Czapski

1996

Inorg. Chem.

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Peroxynitrite is formed when • NO is added to oxygenated solutions of hydrogen-peroxide. The formation rates and the yields of peroxynitrite were determined using the stopped-flow technique at pH 7.5-11.7. The stoichiometry of this process has been determined, and is given by 4The kinetic results are identical to those obtained for the autoxidation of • NO, indicating that the rate determining step of the nitrosation process is the formation of ONOONO (or ONONO or O 2 NNO 2 ), which is the precursor of • NO 2 and of N 2 O 3 . The stoichiometry of the nitrosation process suggests that • NO 2 and/or N 2 O 3 are the reactive species. Competitive kinetic studies demonstrate that the yield of peroxynitrite is independent of • NO concentrations, indicating that the reactive intermediate is N 2 O 3 . The rate constant of the reaction of N 2 O 3 with HO 2 -was determined to be (1.0 ( 0.6) × 10 9 M -1 s -1 , whereas that with H 2 O 2 is at least 4 orders of magnitude lower. The nitrosation of H 2 O 2 by • NO takes place only in the presence of oxygen, and under the conditions of this study, we found no evidence for the direct nitrosation of H 2 O 2 by • NO.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 83%

Formation of Peroxynitrite from the Nitrosation of Hydrogen Peroxide by an Oxygenated Nitric Oxide Solution

Goldstein

Czapski

1996

Inorg. Chem.

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“…Scavengers of RNS particularly N 2 O 3 , which include reduced L -GSH, ascorbic acid and sodium azide were obtained from Sigma-UK. N 2 O 3 scavengers were dissolved in PBS, sterilized through a 0.2 μm filter and added to the cells at 1 mM concentration [18,19]. Scavengers were added to the cells 2 h before and throughout DETA/NO exposure.…”

Section: Methodsmentioning

confidence: 99%

The contribution of N2O3 to the cytotoxicity of the nitric oxide donor DETA/NO: an emerging role for S-nitrosylation

et al. 2013

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The relationship between the biological activity of NO and its chemistry is complex. The objectives of this study were to investigate the influence of oxygen tension on the cytotoxicity of the NO• donor DETA/NO and to determine the effects of oxygen tension on the key RNS (reactive nitrogen species) responsible for any subsequent toxicity. The findings presented in this study indicate that the DETA/NO-mediated cytotoxic effects were enhanced under hypoxic conditions. Further investigations revealed that neither ONOO− (peroxynitrite) nor nitroxyl was generated. Fluorimetric analysis in the presence of scavengers suggest for the first time that another RNS, dinitrogen trioxide may be responsible for the cytotoxicity with DETA/NO. Results showed destabilization of HIF (hypoxia inducible factor)-1α and depletion of GSH levels following the treatment with DETA/NO under hypoxia, which renders cells more susceptible to DETA/NO cytotoxicity, and could account for another mechanism of DETA/NO cytotoxicity under hypoxia. In addition, there was significant accumulation of nuclear p53, which showed that p53 itself might be a target for S-nitrosylation following the treatment with DETA/NO. Both the intrinsic apoptotic pathway and the Fas extrinsic apoptotic pathway were also activated. Finally, GAPDH (glyceraldehyde-3-phosphate dehydrogenase) is another important S-nitrosylated protein that may possibly play a key role in DETA/NO-mediated apoptosis and cytotoxicity. Therefore this study elucidates further mechanisms of DETA/NO mediated cytotoxicity with respect to S-nitrosylation that is emerging as a key player in the signalling and detection of DETA/NO-modified proteins in the tumour microenvironment.

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“…Before concluding this section we must consider an alternative interpretation of eqn. (10). It is well established that when there are strongly electron-attracting groups bound to an amino group, the initial addition of NO+ in electrophilic nitrosation can be reversible and the rate-determining stage becomes proton loss, as in reaction (1 1).…”

Section: First Reactionmentioning

confidence: 99%

“…This mechanism leads to rate law (1 5), which is kinetically equivalent to eqn. (10) when allowance is made for the HN0,-NO2 -equilibrium. has been noted.…”

Section: First Reactionmentioning

confidence: 99%

Kinetics and mechanism of the reaction of nitrous acid with 2,4-dinitrophenylhydrazine

Bernheim¹,

Dobos²,

Doherty³

et al. 1996

J. Chem. Soc., Perkin Trans. 2

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The reactivity of dinitrogen trioxide and of nitrosyl thiocyanate

Cited by 8 publications

References 0 publications

Formation of Peroxynitrite from the Nitrosation of Hydrogen Peroxide by an Oxygenated Nitric Oxide Solution

Formation of Peroxynitrite from the Nitrosation of Hydrogen Peroxide by an Oxygenated Nitric Oxide Solution

The contribution of N2O3 to the cytotoxicity of the nitric oxide donor DETA/NO: an emerging role for S-nitrosylation

Kinetics and mechanism of the reaction of nitrous acid with 2,4-dinitrophenylhydrazine

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