Ayala Marcela, Roman Rosa, Vazquez-Duhalt Rafael
Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
Biochem Biophys Res Commun. 2007 Jun 8;357(3):804-8. doi: 10.1016/j.bbrc.2007.04.020. Epub 2007 Apr 11.
The redox potential of heme-peroxidases varies according to a combination of structural components within the active site and its vicinities. For each peroxidase, this redox potential imposes a thermodynamic threshold to the range of oxidizable substrates. However, the instability of enzymatic intermediates during the catalytic cycle precludes the use of direct voltammetry to measure the redox potential of most peroxidases. Here we describe a novel approach to estimate the redox potential of peroxidases, which directly depends on the catalytic performance of the activated enzyme. Selected p-substituted phenols are used as substrates for the estimations. The results obtained with this catalytic approach correlate well with the oxidative capacity predicted by the redox potential of the Fe(III)/Fe(II) couple.
血红素过氧化物酶的氧化还原电位会根据活性位点及其附近区域内结构成分的组合而变化。对于每种过氧化物酶而言，这种氧化还原电位为可氧化底物的范围设定了一个热力学阈值。然而，催化循环过程中酶中间体的不稳定性使得无法使用直接伏安法来测量大多数过氧化物酶的氧化还原电位。在此，我们描述了一种估算过氧化物酶氧化还原电位的新方法，该方法直接取决于活化酶的催化性能。选定的对位取代酚被用作估算的底物。通过这种催化方法获得的结果与Fe(III)/Fe(II)电对的氧化还原电位所预测的氧化能力密切相关。
