Lu Danying, Grant Murray, Lim Boon Leong
School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.
School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, UK.
Mol Plant. 2025 Jun 2;18(6):938-959. doi: 10.1016/j.molp.2025.05.004. Epub 2025 May 13.
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are essential metabolic coenzymes in prokaryotic and eukaryotic cells, with their reduced forms, NAD(P)H, serving as electron donors for myriad reactions. NADH is mainly involved in catabolic reactions, whereas NADPH is mainly involved in anabolic and antioxidative reactions. The presence of endosymbiont-derived organelles in eukaryotes has made the functional division of NADH and NADPH systems more complex. Chloroplasts in photoautotrophic eukaryotes provide additional sources of reductants, complicating the maintenance of the redox balance of NAD(P)/NAD(P)H compared with heterotrophic eukaryotes. In this review, we discuss the two redox systems in plants and systematically compare them with those in mammals, including the similarities and differences in the biosynthesis and subcellular transport of NAD, the biosynthesis of NADP, and metabolic reactions for the reduction and oxidation of NAD(P)H. We also review the regulation of pyridine nucleotide pools and their ratios in different plant subcellular compartments and the effects of light on these ratios. We discuss the advantages of having both NADH and NADPH systems, highlight current gaps in our understanding of NAD(P)H metabolism, and propose research approaches that could fill in those gaps. The knowledge about NADH and NADPH systems could be used to guide bioengineering strategies to optimize redox-regulated processes and improve energy-use efficiency in crop plants.
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）是原核细胞和真核细胞中必不可少的代谢辅酶，它们的还原形式NAD(P)H作为众多反应的电子供体。NADH主要参与分解代谢反应，而NADPH主要参与合成代谢和抗氧化反应。真核生物中内共生起源细胞器的存在使得NADH和NADPH系统的功能划分更加复杂。与异养真核生物相比，光合自养真核生物中的叶绿体提供了额外的还原剂来源，这使得维持NAD(P)/NAD(P)H的氧化还原平衡变得更加复杂。在这篇综述中，我们讨论了植物中的两种氧化还原系统，并将它们与哺乳动物中的氧化还原系统进行了系统比较，包括NAD生物合成和亚细胞转运、NADP生物合成以及NAD(P)H氧化还原代谢反应的异同。我们还综述了不同植物亚细胞区室中吡啶核苷酸库及其比率的调节以及光照对这些比率的影响。我们讨论了同时拥有NADH和NADPH系统的优势，强调了目前我们对NAD(P)H代谢理解上的差距，并提出了可以填补这些差距的研究方法。关于NADH和NADPH系统的知识可用于指导生物工程策略，以优化氧化还原调节过程并提高作物的能量利用效率。
