Biosystems Technology, Wildau Technical University of Applied Sciences, Wildau, Germany.
Bioelectrochemistry. 2012 Oct;87:9-14. doi: 10.1016/j.bioelechem.2011.07.003. Epub 2011 Jul 24.
The present study reports on the comparison of direct and mediated electron transfer pathways in the interaction of the fungal enzyme cellobiose dehydrogenase (CDH) with the redox protein cytochrome c (cyt c) immobilised at a modified gold electrode surface. Two types of CDHs were chosen for this investigation: a basidiomycete (white rot) CDH from Trametes villosa and a recently discovered ascomycete from the thermophilic fungus Corynascus thermophilus. The choice was based on the pH-dependent interaction of these enzymes with cyt c in solution containing the substrate cellobiose (CB). Both enzymes show rather similar catalytic behaviour at lower pH, dominated by a direct electron exchange with the electrode. With increasing pH, however, also cyt c-mediated electron transfer becomes possible. The pH-dependent behaviour in the presence and in the absence of cyt c is analysed and the potential reaction mechanism for the two enzymes with a different pH-behaviour is discussed.
本研究报告了真菌酶纤维二糖脱氢酶（CDH）与固定在修饰金电极表面的氧化还原蛋白细胞色素 c（cyt c）相互作用中直接和间接电子转移途径的比较。选择了两种类型的 CDH 进行研究：一种来自白腐真菌（白腐菌）的 Trametes villosa CDH 和一种最近发现的来自嗜热真菌 Corynascus thermophilus 的曲霉菌 CDH。选择的依据是这些酶在含有底物纤维二糖（CB）的溶液中与 cyt c 的 pH 依赖性相互作用。两种酶在较低 pH 下表现出相当相似的催化行为，主要是通过与电极的直接电子交换。然而，随着 pH 的增加，也可以实现 cyt c 介导的电子转移。分析了在有和没有 cyt c 存在时的 pH 依赖性行为，并讨论了两种具有不同 pH 行为的酶的潜在反应机制。
