School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia.
J Phys Chem B. 2013 Jun 27;117(25):7569-77. doi: 10.1021/jp404076w. Epub 2013 Jun 12.
Herein we report the mediated electrocatalytic voltammetry of the plant molybdoenzyme nitrate reductase (NR) from Arabidopsis thaliana using the established truncated molybdenum-heme fragment at a glassy carbon (GC) electrode. Methyl viologen (MV), benzyl viologen (BV), and anthraquinone-2-sulfonic acid (AQ) are employed as effective artificial electron transfer partners for NR, differing in redox potential over a range of about 220 mV and delivering different reductive driving forces to the enzyme. Nitrate is reduced at the Mo active site of NR, yielding the oxidized form of the enzyme, which is reactivated by the electro-reduced form of the mediator. Digital simulation was performed using a single set of enzyme dependent parameters for all catalytic voltammetry obtained under different sweep rates and various substrate or mediator concentrations. The kinetic constants from digital simulation provide new insight into the kinetics of the NR catalytic mechanism.
在这里，我们报告了使用在玻碳电极上建立的截短的钼-血红素片段对拟南芥植物钼酶硝酸还原酶（NR）的介导电催化伏安法。甲基紫精（MV）、苄基紫精（BV）和蒽醌-2-磺酸（AQ）被用作 NR 的有效人工电子转移伙伴，它们的氧化还原电位在约 220 mV 的范围内有所不同，并为酶提供不同的还原驱动力。硝酸盐在 NR 的钼活性位点被还原，生成酶的氧化形式，该形式被介体的电还原形式重新激活。使用一组酶依赖参数对在不同扫速和各种底物或介体浓度下获得的所有催化伏安法进行了数字模拟。数字模拟的动力学常数为 NR 催化机制的动力学提供了新的见解。
