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Papel del sulfuro de hidrógeno en la catalización de la formación de NO-ferrohemo

Laxman Poudel¹, Thilini Karunarathna¹, Stephen Baker¹

¹Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA.

Nitric oxide : biology and chemistry

|September 6, 2025

Resumen

El sulfuro de hidrógeno (H2S) acelera significativamente la formación de una nueva molécula de señalización de óxido nítrico (NO), el NO-ferrohemo, en comparación con el glutatión reducido (GSH). Este hallazgo pone de relieve H2S

Área de la Ciencia:

La bioquímica
Fisiología
Biología Química

Sus antecedentes:

El hemo férrico lábil reacciona rápidamente con el óxido nítrico (NO) y los tiolos.
Esta reacción forma NO-ferrohemo, una molécula de señalización involucrada en la dilatación vascular y la homeostasis plaquetaria.
Los glóbulos rojos (glóbulos rojos) son un sitio potencial para la formación de NO-ferrohemo debido a la alta reducción de glutatión (GSH) y la generación de NO.

Objetivo del estudio:

Comparar la reactividad del glutatión reducido (GSH) y el sulfuro de hidrógeno (H2S) en la catalización de la nitrosilación reductora catalizada por tiol.
Investigar la formación de NO-ferrohemo en medios fisiológicamente relevantes, incluida la albúmina sérica humana (HSA) y las membranas de glóbulos rojos.
Elucidar la cinética y los mecanismos de la formación de NO-ferrohemo mediada por H2S y GSH.

Principales métodos:

Análisis cinético comparativo de las reacciones de la hemina con GSH y H2S.
Experimentos realizados en medios fisiológicamente relevantes, como la albúmina sérica humana (ASH) y las membranas de los glóbulos rojos (GRB).
Caracterización de los productos de reacción y de los productos intermedios, incluidos el ácido tionitroso (HSNO) y el nitrosopersulfuro (SSNO-).

Principales resultados:

El sulfuro de hidrógeno (H2S) demostró una constante de velocidad de segundo orden más de 10 veces mayor que el glutatión reducido (GSH).
El H2S exhibe una cinética de reacción más rápida que el GSH en la catalización de la formación de NO-ferrohemo.
La reacción con H2S produce ácido tionitroso (HSNO) y posteriormente nitrosopersulfuro (SSNO-) y polisulfuro.

Conclusiones:

El sulfuro de hidrógeno (H2S) es un catalizador más potente que el GSH para la nitrosilación reductiva catalizada por tiol del hemo férrico lábil.
La mayor reactividad del H2S se atribuye a su mayor solubilidad en ambientes lipofílicos y menor impedimento estérico en comparación con el GSH.
Estos hallazgos sugieren que la formación de NO-ferrohemo catalizado por H2S es una vía significativa en la señalización biológica de NO.

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