Investigation of the mediated electron transfer mechanism of cellobiose dehydrogenase at cytochrome c-modified gold electrodes

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• 作者：David Sarauli ; Rol ; Ludwig ; Dietmar Haltrich ; Lo Gorton ; Fred Lisdat
• 关键词：Cellobiose dehydrogenase ; Direct electron transfer ; Mediated electron transfer ; Cytochrome c ; Immobilised enzyme
• 刊名：Bioelectrochemistry
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：87
• 期：Complete
• 页码：9-14
• 全文大小：770 K

文摘

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.