Articolo in rivista, 2003,

Methylene blue photosensitized oxidation of hypotaurine in the presence of azide generates reactive nitrogen species: formation of nitrotyrosine

Pecci L Montefoschi G , Antonucci A , Costa M , Cavallini D

In our previous study on the hypotaurine (HTAU) oxidation by methylene blue (MB) photochemically generated singlet oxygen (1O2) we found that azide, usually used as 1O2 quencher, produced, instead, an evident enhancing effect on the oxidation rate [L. Pecci, M. Costa, G. Montefoschi, A. Antonucci, D. Cavallini, Biochem. Biophys. Res. Commun. 254 (1999) 661-665]. We show here that this effect is strongly dependent on pH, with a maximum at approximately pH 5.7. When the MB photochemical system containing HTAU and azide was performed in the presence of tyrosine, 3-nitrotyrosine was produced with maximum yield at pH 5.7, suggesting that azide, by the combined action of HTAU and singlet oxygen, generates nitrogen species which contribute to tyrosine nitration. In addition to HTAU, cysteine sulfinic acid, and sulfite were found to induce the formation of 3-nitrotyrosine. No detectable tyrosine nitration was observed using taurine, the oxidation product of HTAU, or thiol compounds such as cysteine and glutathione. It is shown that during the MB photooxidation of HTAU in the presence of azide, nitrite, and nitrate are produced. Evidences are presented, indicating that nitrite represents the nitrogen species involved in the production of 3-nitrotyrosine. A possible mechanism accounting for the enhancing effect of azide on the photochemical oxidation of HTAU and the production of nitrogen species is proposed.

Biochemical and biophysical research communications (Print) 301 , pp. 411–416

Keywords

CNR authors

Pecci Laura, Antonucci Antonio

CNR institutes

IBPM – Istituto di biologia e patologia molecolari

ID: 11351

Year: 2003

Type: Articolo in rivista

Creation: 2009-06-16 00:00:00.000

Last update: 2009-06-16 00:00:00.000

External links

OAI-PMH: Dublin Core

OAI-PMH: Mods

OAI-PMH: RDF

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:11351