Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden.
Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden; Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
Bioelectrochemistry. 2021 Apr;138:107699. doi: 10.1016/j.bioelechem.2020.107699. Epub 2020 Nov 10.
Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.
详细的阻抗和伏安法研究表明，六聚体八血红素亚硝酸盐还原酶固定在碳基纳米材料上，特别是纳米管和纳米粒子上，得到了很好的生物电化学亚硝酸盐还原。对酶修饰电极上亚硝酸盐的阻抗数据分析表明，没有涉及亚硝酸盐还原的长寿命中间产物。生物修饰电极的循环伏安曲线具有双 S 形，这表明在碳载体上存在两种酶取向。确定了最大（限制）催化电流，并通过应用混合动力学方程进行校正，为每个催化波/每个酶取向绘制了塔菲尔依赖性。最后，提出了两种生物电催化过程中限速过程的方案，即低电位和高电位取向。
