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Published on: December 4, 2017
Electroquímica directa de una deshidrogenasa de sulfito bacteriana
Kondo-François Aguey-Zinsou1, Paul V Bernhardt, Ulrike Kappler
1Department of Chemistry, Centre for Metals in Biology, University of Queensland, Brisbane, 4072, Australia.
Journal of the American Chemical Society
|January 9, 2003
Resumen
La sulfito deshidrogenasa de Starkeya novella fue estudiada utilizando métodos electroquímicos. Los investigadores determinaron sus potenciales redox y la constante de Michaelis, encontrando valores comparables a los ensayos de solución.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Bioelectroquímica y bioelectroquímica.
Sus antecedentes:
- La sulfito deshidrogenasa (SDH) de Starkeya novella es una enzima clave en la oxidación del azufre.
- Es un heterodímero alfa-beta que contiene un cofactor de molibdeno (Mo) y una subunidad de hemo c.
- Su mecanismo catalítico es similar al de las sulfitooxidasas eucariotas.
Objetivo del estudio:
- Para investigar las propiedades redox de Starkeya novella sulfite dehydrogenase.
- Para determinar los parámetros cinéticos de la enzima utilizando técnicas electroquímicas.
- Para comparar el comportamiento de la enzima inmovilizada en una superficie de electrodo con ensayos basados en soluciones.
Principales métodos:
- Se empleó voltametría de película proteica para estudiar la enzima inmovilizada.
- Se utilizó la potencialometría de redox para determinar los potenciales del punto medio.
- Se realizaron ensayos electroquímicos para medir la constante de Michaelis (Km).
Principales resultados:
- Se identificaron distintas respuestas redox centradas en Mo y hemo.
- Potenciales del punto medio determinados: E m,8 (Fe III/II) +177 mV, E m,8 (Mo VI/V) +211 mV, y E m,8 (Mo V/IV) -118 mV.
- Se observó un voltammograma de estado estacionario después de la adición de sulfito y se determinó un Km aparente de 26 μm.
Conclusiones:
- El estudio caracterizó con éxito el comportamiento redox de Starkeya novella sulfite dehydrogenase utilizando métodos electroquímicos.
- La enzima inmovilizada exhibe propiedades cinéticas comparables a las de la solución.
- Este trabajo proporciona información sobre el mecanismo catalítico de la enzima y el potencial para aplicaciones bioelectroquímicas.
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