Applied Physics Laboratory, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, USA.
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, USA.
Sci Rep. 2021 Jan 8;11(1):180. doi: 10.1038/s41598-020-79761-6.
Nearly a fourth of all enzymatic activities is attributable to oxidoreductases, and the redox reactions supported by this vast catalytic repertoire sustain cellular metabolism. In many biological processes, reduction depends on hydride transfer from either reduced nicotinamide adenine dinucleotide (NADH) or its phosphorylated derivative (NADPH). Despite longstanding efforts to regenerate NADPH by various methods and harness it to support chemoenzymatic synthesis strategies, the lack of product purity has been a major deterrent. Here, we demonstrate that a nanostructured heterolayer Ni-CuO-Cu cathode formed by a photoelectrochemical process has unexpected efficiency in direct electrochemical regeneration of NADPH from NADP. Remarkably, two-thirds of NADP was converted to NADPH with no measurable production of the inactive (NADP) dimer and at the lowest reported overpotential [- 0.75 V versus Ag/AgCl (3 M NaCl) reference]. Sputtering of nickel on the copper-oxide electrode nucleated an unexpected surface morphology that was critical for high product selectivity. Our results should motivate design of integrated electrolyzer platforms that deploy this heterogeneous catalyst for direct electrochemical regeneration of NADH/NADPH, which is central to design of next-generation biofuel fermentation strategies, biological solar converters, energy-storage devices, and artificial photosynthesis.
近四分之一的酶活性归因于氧化还原酶，而这个庞大的催化库所支持的氧化还原反应维持着细胞代谢。在许多生物过程中，还原取决于从还原型烟酰胺腺嘌呤二核苷酸（NADH）或其磷酸化衍生物（NADPH）转移氢。尽管人们长期以来一直试图通过各种方法来再生 NADPH 并利用它来支持化学酶合成策略，但缺乏产品纯度一直是一个主要障碍。在这里，我们证明通过光电化学过程形成的具有异质层结构的 Ni-CuO-Cu 阴极在直接电化学再生 NADP 为 NADPH 方面具有意想不到的效率。值得注意的是，三分之二的 NADP 转化为 NADPH，而没有可测量的无活性（NADP）二聚体的生成，并且报道的过电位最低[-0.75 V 相对于 Ag/AgCl（3 M NaCl）参比]。镍溅射在氧化铜电极上引发了意想不到的表面形态，这对于高产物选择性至关重要。我们的结果应该激发集成电解槽平台的设计，该平台使用这种多相催化剂直接电化学再生 NADH/NADPH，这是设计下一代生物燃料发酵策略、生物太阳能转换器、储能装置和人工光合作用的核心。
