Cosnier S, Da Silva S, Shan D, Gorgy K
Département de Chimie Moléculaire UMR-5250, ICMG FR-2607, CNRS Université Joseph Fourier, BP-53, 38041 Grenoble Cedex 9, France.
Bioelectrochemistry. 2008 Nov;74(1):47-51. doi: 10.1016/j.bioelechem.2008.04.011. Epub 2008 Apr 16.
The immobilization of nitrate reductase (NR) was performed by entrapment in a laponite clay gel and cross-linking by glutaraldehyde. In presence of nitrate and methyl viologen, a catalytic current appeared at -0.60 V illustrating the enzymatic reduction of nitrate into nitrite via the reduced form of the freely diffusing methyl viologen. The electropolymerization of a water-soluble pyrrole viologen derivative within the interlamellar spaces and channels of the host clay matrix successfully carried out the electrical wiring of the entrapped NR. Rotating disk measurements led to the determination of kinetic constants, namely k(2)=10.7 s(-1) and K(M)=7 microM. These parameters reflect the efficiency of the electro-enzymatic reduction of nitrate and the substrate affinity for the immobilized enzyme.
通过将硝酸还原酶（NR）包埋在锂皂石粘土凝胶中并用戊二醛交联来实现其固定化。在硝酸盐和甲基紫精存在的情况下，在 -0.60 V 处出现催化电流，这表明通过自由扩散的甲基紫精的还原形式将硝酸盐酶促还原为亚硝酸盐。在主体粘土基质的层间空间和通道内成功进行了水溶性吡咯紫精衍生物的电聚合，实现了包埋的 NR 的电气连接。旋转圆盘测量得出了动力学常数，即 k(2)=10.7 s(-1) 和 K(M)=7 microM。这些参数反映了硝酸盐电酶还原的效率以及固定化酶对底物的亲和力。
