Direct electron transfer in the system gold electrode–recombinant horseradish peroxidases

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• 作者：Ferapontova ; Elena E. ; Grigorenko ; Vitaly G. ; Egorov ; Alexey M. ; Bö ; rchers ; Torsten ; et. al.
• 关键词：Bioelectrocatalysis ; Recombinant horseradish peroxidase ; Heterogeneous direct electron transfer ; Gold electrode
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2001
• 期刊代码：27_00220728
• 类别：ph
• 出版时间：August 10, 2001
• 卷：509
• 期：1
• 页码：19-26
• 文件大小：135 K

摘要

The kinetics of the bioelectrocatalytic reduction of hydrogen peroxide has been studied at gold electrodes modified with different forms of horseradish peroxidase (HRP). Native HRP, wild type recombinant HRP (rec-HRP) and its two mutant forms containing a six-histidine tag at the C- or N-terminus, C_Hisrec-HRP and N_Hisrec-HRP, respectively, have been used for an adsorptive modification of the gold electrodes. The histidine sequences, i.e. histidine tags, were introduced into the peroxidase structure by genetic engineering of non-glycosylated rec-HRP using an Escherichia coli expression system. Experiments with a gold rotating disc electrode demonstrated that electrodes with the adsorbed rec-HRP forms exhibited high and stable current response to H₂O₂ due to its bioelectrocatalytic reduction based on direct (mediatorless) ET between gold and the active site of HRP. The heterogeneous ET rate constants were evaluated to be in the order of 20 or 33 s⁻¹ between rec-HRP or its histidine mutants and gold, respectively, in 0.01 M phosphate buffer (pH 7.4) containing 0.15 M NaCl. The increase in the heterogeneous ET rate found for C_Hisrec-HRP and N_Hisrec-HRP is probably due to the interaction of the histidine tag with the electrode surface. The kinetic data demonstrate that new possibilities for enhancing the catalytic activity of the enzyme at the electrodesolution interface can be achieved by genetic engineering design of the enzyme molecules.