Vuorilehto K, Lütz S, Wandrey C
Institute of Biotechnology 2, Research Centre of Jülich, D-52425 Jülich, Germany.
Bioelectrochemistry. 2004 Dec;65(1):1-7. doi: 10.1016/j.bioelechem.2004.05.006.
Nicotinamide coenzymes nicotinamide adenine dinucleotide (NAD(+)) and nicotinamide adenine dinucleotide phosphate (NADP(+)) were electrochemically reduced to NADH and NADPH, respectively. As direct reduction of nicotinamide coenzymes leads to inactive by-products, an indirect method using (pentamethylcyclopentadienyl-2,2'-bipyridine aqua) rhodium (III) as the mediator, was applied. A phosphate buffer solution, pH 8, with 1-10 mM NAD(P)(+) and 2.5-200 microM mediator, was pumped through a glassy carbon packed bed cathode. Virtually all the NAD(P)(+) was reduced to NAD(P)H in the cell. No sign of mediator loss due to side-reactions was detected though the mediator molecules shuttled hundreds of times between the oxidised and the reduced form. Adsorption of mediator molecules on the surface of the carbon cathode was found to be important for the reduction process. Due to strong adsorption, only minute amounts of mediator were consumed.
烟酰胺辅酶烟酰胺腺嘌呤二核苷酸（NAD(+)）和烟酰胺腺嘌呤二核苷酸磷酸（NADP(+)）分别被电化学还原为NADH和NADPH。由于烟酰胺辅酶的直接还原会产生无活性的副产物，因此采用了一种以（五甲基环戊二烯基-2,2'-联吡啶水合）铑（III）作为介质的间接方法。将pH为8、含有1 - 10 mM NAD(P)(+)和2.5 - 200 μM介质的磷酸盐缓冲溶液泵入玻璃碳填充床阴极。实际上，细胞内所有的NAD(P)(+)都被还原为NAD(P)H。尽管介质分子在氧化态和还原态之间穿梭了数百次，但未检测到由于副反应导致的介质损失迹象。发现介质分子在碳阴极表面的吸附对还原过程很重要。由于强烈吸附，仅消耗了微量的介质。
