Graphite electrodes modified with Neurospora crassa cellobiose dehydrogenase: Comparative electrochemical characterization under direct and mediated electron transfer

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• 作者：Gabor Kovacs ; Roberto Ortiz ; Vasile Coman ; Wolfgang Harreither ; Ionel Catalin Popescu ; Rol ; Ludwig ; Lo Gorton
• 关键词：Cellobiose dehydrogenase ; Amperometric biosensors ; Direct electron transfer ; Mediated electron transfer ; Flow injection analysis
• 刊名：Bioelectrochemistry
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：88
• 期：Complete
• 页码：84-91
• 全文大小：664 K

文摘

The electrochemical characterization of a class II cellobiose dehydrogenase (CDH), from the ascomycete fungus Neurospora crassa, adsorbed on graphite (G), was performed in regard to direct (DET) and mediated electron transfer (MET). The effects of the applied potential, mediator (1,4 benzoquinone) concentration and flow carrier pH on the amperometric response of the G/CDH modified electrodes were investigated under flow conditions. From the calibration curves, recorded at two pH values (5.2 and 7.0) for nine different sugars, the kinetic and the analytical parameters were evaluated under DET and MET operation modes. These results together with those obtained from long term operational stability measurements showed that: (i) for all nine investigated sugars the sensitivity was higher for MET than for DET and for pH 5.2 compared to pH 7.0; (ii) irrespective of DET or MET operation mode, the sensitivity of the new enzyme towards the investigated sugars decreased in the following sequence: cellobiose > lactose > (cellotriose ¡Ö cellopentaose) > > (maltotriose ¡Ö maltotetraose ¡Ö maltopentaose) > (maltose ¡Ö glucose); (iii) for all tested substrates, the apparent CDH affinity was roughly higher in DET than in MET operation mode.