Peroxynitrite mediates the oxidation of the sulphinic group of both HTAU (hypotaurine) and CSA (cysteine sulphinic acid), producing the respective sulphonates, TAU (taurine) and CA (cysteic acid). The reaction is associated with extensive oxygen uptake, suggesting that HTAU and CSA are oxidized by the one-electron transfer mechanism to sulphonyl radicals, which may initiate an oxygen-dependent radical chain reaction with the sulphonates as final products. Besides the one-electron mechanism, HTAU and CSA can be oxidized by the two-electron pathway, leading directly to sulphonate formation without oxygen consumption. The apparent second-order rate constants for the direct reaction of peroxynitrite with HTAU and CSA at pH 7.4 and 25 °C are 77.4±5 and 76.4±9 M−1·s−1 respectively. For both sulphinates, the apparent second-order rate constants increase sharply with decrease in pH, and the sigmoidal curves obtained are consistent with peroxynitrous acid as the species responsible for sulphinate oxidation. The kinetic data, together with changes in oxygen uptake, sulphinate depletion, sulphonate production, and product distribution of nitrite and nitrate, suggest that oxidation of sulphinates by peroxynitrite may take place by the two reaction pathways whose relative importance depends on reagent concentrations and pH value. In the presence of bicarbonate, the direct reaction of sulphinates with peroxynitrite is inhibited and the oxidative reaction probably involves only the radicals •NO2 and CO3•−, generated by decomposition of the peroxynitrite-CO2 adduct.
Skip Nav Destination
Article navigation
July 2005
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkEditorial Board
Research Article|
June 21 2005
Oxidation of hypotaurine and cysteine sulphinic acid by peroxynitrite
Mario FONTANA;
Mario FONTANA
1
1Department of Biochemical Sciences ‘A. Rossi Fanelli’ and Institute of Molecular Biology and Pathology of CNR, University of Rome ‘La Sapienza’, P.le Aldo Moro 5, I-00185 Rome, Italy
1To whom correspondence should be addressed (email mario.fontana@uniroma1.it).
Search for other works by this author on:
Donatella AMENDOLA;
Donatella AMENDOLA
1Department of Biochemical Sciences ‘A. Rossi Fanelli’ and Institute of Molecular Biology and Pathology of CNR, University of Rome ‘La Sapienza’, P.le Aldo Moro 5, I-00185 Rome, Italy
Search for other works by this author on:
Emanuela ORSINI;
Emanuela ORSINI
1Department of Biochemical Sciences ‘A. Rossi Fanelli’ and Institute of Molecular Biology and Pathology of CNR, University of Rome ‘La Sapienza’, P.le Aldo Moro 5, I-00185 Rome, Italy
Search for other works by this author on:
Alberto BOFFI;
Alberto BOFFI
1Department of Biochemical Sciences ‘A. Rossi Fanelli’ and Institute of Molecular Biology and Pathology of CNR, University of Rome ‘La Sapienza’, P.le Aldo Moro 5, I-00185 Rome, Italy
Search for other works by this author on:
Laura PECCI
Laura PECCI
1Department of Biochemical Sciences ‘A. Rossi Fanelli’ and Institute of Molecular Biology and Pathology of CNR, University of Rome ‘La Sapienza’, P.le Aldo Moro 5, I-00185 Rome, Italy
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
October 06 2004
Revision Received:
February 08 2005
Accepted:
March 02 2005
Accepted Manuscript online:
March 02 2005
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London
2005
Biochem J (2005) 389 (1): 233–240.
Article history
Received:
October 06 2004
Revision Received:
February 08 2005
Accepted:
March 02 2005
Accepted Manuscript online:
March 02 2005
Citation
Mario FONTANA, Donatella AMENDOLA, Emanuela ORSINI, Alberto BOFFI, Laura PECCI; Oxidation of hypotaurine and cysteine sulphinic acid by peroxynitrite. Biochem J 1 July 2005; 389 (1): 233–240. doi: https://doi.org/10.1042/BJ20041696
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.