INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Insights into the mechanism of the reaction between Hydrogen sulfide and peroxynitrite
Autor/es:
ERNESTO CUEVASANTA; ARI ZEIDA; SEBASTIÁN CARBALLAL; RUDOLF WEEDMAN; URIEL N. MORZÁN; MADIA TRUJILLO; RAFAEL RADI; DARIO A. ESTRIN; MILOS R. FILIPOVIC; BEATRIZ ALVAREZ
Revista:
FREE RADICAL BIOLOGY AND MEDICINE
Editorial:
ELSEVIER SCIENCE INC
Referencias:
Lugar: Amsterdam; Año: 2015 vol. 80 p. 93 - 93
ISSN:
0891-5849
Resumen:
Hydrogen sulfide and peroxynitrite are endogenously generated molecules that participate in biologically-relevant pathways. A revision of the kinetic features of the reaction between peroxynitrite and hydrogen sulfide revealed a complex process. The rate constant of peroxynitrite decay, (6.65±0.08)×103 M−1 s−1 in 0.05 M sodium phosphate buffer (pH 7.4, 37 °C), was affected by the concentration of buffer. Theoretical modeling suggested that, as in the case of thiols, the reaction is initiated by the nucleophilic attack of HS− on the peroxide group of ONOOH by a typical bimolecular nucleophilic substitution, yielding HSOH and NO2−. In contrast to thiols, the reaction then proceeds to the formation of distinct products that absorb near 408 nm. Experiments in the presence of scavengers and carbon dioxide showed that free radicals are unlikely to be involved in the formation of these products. The results are consistent with product formation involving the reactive intermediate HSSH and its fast reaction with a second peroxynitrite molecule. Mass spectrometry and UV-Vis absorption spectra predictions suggest that at least one of the products is HSNO2 or its isomer HSONO.