Comparison of the reactivity of nine nitrous acid scavengers

Fitzpatrick, John; Meyer, Thomas A.; O’Neill, Marion E.; Williams, D. Lyn H.

doi:10.1039/p29840000927

Cited by 38 publications

(30 citation statements)

References 4 publications

(4 reference statements)

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“…To remove endogenous nitrite, ammonium nilfamate (final concentration 5 or 25 mM) was added to the TCA solution in most of the experiments. Sulfamate is known to react rapidly and completely with nitrite and is probably the most widely used trap for nitrite (Saville, 1958: Fitzpatrick et al, 1984. In a control authentic GSNO at 0.5 pM concentration, corresponding to the level of the endogenous component in the extraction solution, was found to be unaffected by sulfaniate.…”

Section: Purification and Identification Of Endogenous Gsno In Cerebementioning

confidence: 96%

S‐Nitrosoglutathione in Rat Cerebellum: Identification and Quantification by Liquid Chromatography‐Mass Spectrometry

Gutteck-Amsler

Zollinger

et al. 1997

Journal of Neurochemistry

169

102

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Given the extreme lability and the facile inactivation of the messenger nitric oxide (NO) by many reactive biochemical species, it has been suggested that some intermediate compounds, for example, S‐nitrosothiols, may act to stabilize NO and at the same time to preserve its biological activity. To test this hypothesis, we investigated if the S‐nitrosothiol of glutathione, which is the predominant low molecular weight thiol in CNS, is present in the rat brain. The HPLC analysis of cerebellar extract from [35S]cysteine‐prelabeled slices suggested that S‐nitrosoglutathione (GSNO) was indeed present in rat brain. To detect endogenous GSNO, a methodology based on liquid chromatography‐mass spectrometry was developed. Besides an unequivocal identification of the endogenous GSNO, this method also permitted its precise quantification using 15N‐labeled GSNO ([15N]‐GSNO) as internal standard. GSNO level in adult cerebellum amounts to 15.4 ± 1.4 pmol/mg of protein. This is the first direct demonstration of the presence of endogenous GSNO in CNS. The packaging of NO in the form of GSNO might serve to facilitate its transport, prolong its life, and target its delivery to specific effectors.

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Section: Purification and Identification Of Endogenous Gsno In Cerebementioning

confidence: 96%

S‐Nitrosoglutathione in Rat Cerebellum: Identification and Quantification by Liquid Chromatography‐Mass Spectrometry

Gutteck-Amsler

Zollinger

et al. 1997

Journal of Neurochemistry

169

102

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“…The values obtained for the nitrosation process k n ¼ k 3 K 2 , and for the denitrosation process k d ¼ k À3 for the three Gs studied are showed in Table 1. In all cases the values for the nitrosation process are lower than that found in the nitrosation of urea [25] and very far from the encounter controlled limit (7 Â 10 9 M À1 s À1 for neutral substrates). [7] This behaviour differs from that of most amines, whose basicity causes them to be mostly protonated and react with nitrosating agents through the free base, more nucleophilic than neutral Gs, leading to much higher values for the nitrosation bimolecular rate constants and close to the diffusion controlled limit.…”

Section: Resultsmentioning

confidence: 81%

“…This fits in to the pattern of behaviour found for other nitrogen nucleophiles of low basicity, such as ureas and amides, which is quite different to that found for the much more basic amines. Interestingly the much less basic 2,4-dinitroaniline [25] behaves more like an amide or urea. Finally, the analysis of the Brö nsted slopes suggest that in the transition state the protonation of nitrosoguanidine is nearly complete.…”

Section: Resultsmentioning

confidence: 99%

Kinetic study of nitrosation of guanidines

Fernández

Hervés

Parajó

2008

J of Physical Organic Chem

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The kinetics of the nitrosation reaction of three guanidines, dicyandiamide, N,N(-dimethyl-N 00 -cyanoguanidine and guanidine have been studied. The nitrosation rate is first order with respect to both the guanidine and acid concentration. The absence of catalysis by nucleophilic anions, the observed general acid-base catalysis and the observed deuterium isotope effect lead us to propose mechanism for the nitrosation of guanidines similar to that which operates in the case of the amides and ureas, in which a slow proton transfer is the rate determining step. From this mechanism we were able to obtain the values of the rate constants for the nitrosation and denitrosation processes. The catalytic constants in presence of buffers were also obtained and the analysis of the Brö nsted slopes suggests a process with a transition state more similar to reactants than products.

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“…At low acidity ca. 0.1 M, sulfamic acid is the more reactive towards nitrosation, whereas at 1 M acid, hydrazoic acid is the better trap (2).…”

Section: Nature Of Nitrous Acid Trapsmentioning

confidence: 99%

Quantitative Aspects of Nitrosamine Denitrosation

Williams¹

1994

ACS Symposium Series

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The kinetics of denitrosation of nitrosamines have been studied under acid conditions in the presence of a sufficient quantity of a nitrous acid trap which ensures that denitrosation to the secondary amine is irreversible. A range of nitrous acid traps, nucleophilic catalysts and solvent systems have been examined for five representative nitrosamine structures in an attempt to establish the most favourable experimental conditions for effecting denitrosation.Treatment of nitrosamines in acid solution, sometimes in the presence of nucleophiles, leads to the formation of the corresponding secondary amines and free nitrous acid. This reaction (denitrosation) can be made quantitative if a trap for the nitrous acid is added in sufficient concentration to ensure that the reverse reaction (nitrosation) cannot compete. This article describes the effect of (a) different nitrous acid traps, (b) the concentration and nature of the nucleophile, (c) the structure of the nitrosamine, and (d) the solvent, on the rate of denitrosation. The objective in this work is to establish the most favourable reaction conditions available for effecting denitrosation of any given nitrosamine.Although nitrosamines are generally not naturally-occurring compounds they can readily be formed, particularly from secondary amines and a nitrosating agent. They often crop up as very minor by-products in a whole range of materials including foodstuffs, dyes, detergents, herbicides etc. It is therefore important, given their well-known carcinogenic properties*, that procedures are available for their safe destruction. Over the years a number of methods have been examined with this end in view. Two such reactions are given in equations 1 and 2, in which, respectively, nitrosamines are reduced to amines and hydrazines (equation 1), or are subjected to thermal or photochemical degradation (equation 2).

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Comparison of the reactivity of nine nitrous acid scavengers

Cited by 38 publications

References 4 publications

S‐Nitrosoglutathione in Rat Cerebellum: Identification and Quantification by Liquid Chromatography‐Mass Spectrometry

S‐Nitrosoglutathione in Rat Cerebellum: Identification and Quantification by Liquid Chromatography‐Mass Spectrometry

Kinetic study of nitrosation of guanidines

Quantitative Aspects of Nitrosamine Denitrosation

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