Fleming Barry D, Zhang Jie, Bond Alan M, Bell Stephen G, Wong Luet-Lok
School of Chemistry, Monash University, Clayton, Victoria 3800, Australia.
Anal Chem. 2005 Jun 1;77(11):3502-10. doi: 10.1021/ac048151y.
The underlying electron-transfer and coupled chemical processes associated with biologically important catalytic reactions can be resolved using a combination of Fourier transform ac voltammetry with an analysis of the separated dc and ac components. This outcome can be achieved because the response associated with generation of the catalytic current is essentially confined to the steady-state dc component, whereas the electron-transfer step is dominant in the fundamental and higher harmonics. For the mediated oxidation of glucose with glucose oxidase, it was found that the underlying reversible redox chemistry of the mediator, ferrocenemonocarboxylic acid, as detected in the third and higher harmonics, was totally unaffected by introduction of the catalytic process. In contrast, for the catalytic reduction of molecular oxygen by cytochrome P450, slight changes in the P450 redox process were detected when the catalytic reaction was present. Simulations of a simple catalytic reaction scheme support the fidelity of this novel FT ac voltammetric approach for examining mechanistic nuances of catalytic forms of electrochemical reaction schemes.
通过将傅里叶变换交流伏安法与分离的直流和交流成分分析相结合，可以解析与生物学上重要的催化反应相关的潜在电子转移和耦合化学过程。之所以能够实现这一结果，是因为与催化电流产生相关的响应基本上局限于稳态直流成分，而电子转移步骤在基波和更高谐波中占主导地位。对于用葡萄糖氧化酶介导的葡萄糖氧化，发现在三次及更高谐波中检测到的介质二茂铁单羧酸的潜在可逆氧化还原化学，完全不受催化过程引入的影响。相比之下，对于细胞色素P450催化的分子氧还原，当存在催化反应时，检测到P450氧化还原过程有轻微变化。对一个简单催化反应方案的模拟支持了这种新颖的傅里叶变换交流伏安法用于研究电化学反应方案催化形式的机理细微差别的准确性。
