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Hemo/O2/*NO reactividad de la óxido nítrico dioxigenasa (NOD): nitratación fenólica a través de un presunto
Mark P Schopfer1, Biplab Mondal, Dong-Heon Lee
1Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Journal of the American Chemical Society
|July 25, 2009
Resumen
Los complejos de hemo-superoxo reaccionan con el óxido nítrico (NO) para formar compuestos de nitrato-hierro (III), imitando las dioxigenasas del óxido nítrico. Esta química hemo puede involucrar intermediarios de peroxinitrito y conducir a la nitratación del sustrato.
Área de la Ciencia:
- Química bioorgánica Química bioorgánica.
- Química de la oxidación Química de la oxidación
- La señalización del óxido nítrico.
Sus antecedentes:
- El óxido nítrico (NO) es una molécula de señalización crucial involucrada en varios procesos fisiológicos.
- Las dioxigenasas de óxido nítrico (NOD) son proteínas hemo que desintoxican el NO.
- Comprender la reactividad de los complejos hemo con el NO es esencial para elucidar el metabolismo biológico del NO.
Objetivo del estudio:
- Para investigar la reacción de un complejo hemo-superoxo con óxido nítrico.
- Para explorar la posible participación de los intermediarios de peroxinitrito en esta reacción.
- Para imitar la actividad enzimática de las dioxigenasas de óxido nítrico en un sistema modelo.
Principales métodos:
- Síntesis y caracterización de un complejo hemo-superoxo de tetraarilporfirinato sustituido por orto-difluoro.
- Reacción del complejo hemo-superoxo con el óxido nítrico.
- Cristalografía de rayos X para determinar la estructura de los productos de reacción.
- Investigación de la reacción en presencia de sustratos exógenos como el 2,4-di-tert-butylphenol.
Principales resultados:
- El complejo hemo-superoxo reaccionó con el óxido nítrico para producir un compuesto nitrato-hierro (III).
- Un intermediario de peroxinitrito estuvo implicado en la vía de reacción.
- En presencia de 2,4-di-tercio-butilofenol, se produjo la o-nitración del fenol, dando como resultado 2,4-di-tercio-butilo-6-nitrofenol.
- El producto final de hierro fue identificado como una especie hidroxo-hierro (III).
Conclusiones:
- La química hemo/O2) /NO puede conducir a la formación de especies de nitrato-hierro (III), imitando la actividad de NOD.
- Los intermediarios de peroxinitrito pueden estar involucrados, causando potencialmente daño oxidativo y nitrativo a los sustratos exógenos.
- Este sistema modelo proporciona información sobre la compleja reactividad de las proteínas hemo con el óxido nítrico.
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