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Sobre la distinción entre nitroxilo y óxido nítrico utilizando nitróxidos de nitronilo.
Uri Samuni1, Yuval Samuni, Sara Goldstein
1Department of Chemistry and Biochemistry, Queens College, City University of New York, Flushing, New York 11367, USA.
Journal of the American Chemical Society
|May 28, 2010
Resumen
La detección de óxido nítrico (NO) utilizando nitróxidos de nitronilo se complica por el óxido nítrico (HNO) que reacciona para formar hidroxilaminas. Los nitróxidos de nitronilo pueden distinguir el NO del HNO sólo en bajas concentraciones.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Química Biología química.
- Fisiología Fisiología Fisiología.
Sus antecedentes:
- La detección precisa de óxido nítrico (NO) e hidróxido de nitrosilo (HNO) es crucial para comprender sus funciones biológicas.
- Los nitróxidos de nitronilo, como C-PTIO, se utilizan comúnmente para detectar NO a través de su reacción formando imino nitróxidos.
Objetivo del estudio:
- Investigar el mecanismo de reacción entre el HNO y los nitróxidos de nitronilo.
- Para determinar la constante de velocidad para la reacción de HNO con C-PTIO.
- Evaluar el potencial de los nitróxidos de nitronilo para diferenciar entre NO y HNO.
Principales métodos:
- Utilizó la sal de Angeli (AS) como donante de HNO.
- Utilizó la metmioglobina como agente competidor para cuantificar las velocidades de reacción.
- Análisis espectroscópico para identificar productos de reacción.
Principales resultados:
- El HNO reacciona fácilmente con los nitróxidos de nitronilo (por ejemplo, C-PTIO, PTIO) formando imino nitróxidos e hidroxilaminas.
- Se determinó que la constante de velocidad para la reducción de C-PTIO por HNO es (1.4 ± 0.2) x 10^5 M^-1 s^-1 a pH 7.0.
- La conversión completa a iminohidroxilamina ocurre en proporciones más altas de AS a nitróxido de nitronilo.
Conclusiones:
- Los nitróxidos de nitronilo se reducen por HNO a hidroxilaminas y posteriormente se convierten en nitróxidos de imino e imino hidroxilaminas.
- La vía de reacción permite discriminar entre NO y HNO sólo cuando la concentración de nitróxido de nitronilo es significativamente menor que la producción de HNO.
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