Nicotinamide adenine dinucleotide phosphate

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Nicotinamide adenine dinucleotide phosphate
NADP+ phys.svg
3D model (JSmol)
ECHA InfoCard 100.000.163
Molar mass 744.416 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Nicotinamide adenine dinucleotide phosphate, abbreviated NADP+ or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADPH as a reducing agent.

NADPH is the reduced form of NADP+. NADP+ differs from NAD+ in the presence of an additional phosphate group on the 2' position of the ribose ring that carries the adenine moiety.

In plants[edit]

In photosynthetic organisms, NADPH is produced by ferredoxin-NADP+ reductase in the last step of the electron chain of the light reactions of photosynthesis. It is used as reducing power for the biosynthetic reactions in the Calvin cycle to assimilate carbon dioxide and help turn the carbon dioxide into glucose. It is also needed in the reduction of nitrate into ammonia for plant assimilation in nitrogen cycle. It is also needed in the production of oils.

In animals[edit]

The major source of NADPH in animals and other non-photosynthetic organisms is the pentose phosphate pathway.

However, there are several other lesser-known mechanisms of generating NADPH, all of which depend on the presence of mitochondria. The key enzymes in these processes are: NADP-linked malic enzyme, NADP-linked isocitrate dehydrogenase, NADP-linked glutamate dehydrogenase and nicotinamide nucleotide transhydrogenase.[1] The isocitrate dehydrogenase mechanism appears to be the major source of NADPH in fat and possibly also liver cells.[2] Also, in mitochondria, NADH kinase produces NADPH and ADP, using NADH and ATP as substrates.


NADPH provides the reducing equivalents for biosynthetic reactions and the oxidation-reduction involved in protecting against the toxicity of reactive oxygen species (ROS), allowing the regeneration of glutathione (GSH).[3] NADPH is also used for anabolic pathways, such as cholesterol synthesis and fatty acid chain elongation.

The NADPH system is also responsible for generating free radicals in immune cells. These radicals are used to destroy pathogens in a process termed the respiratory burst.[4] It is the source of reducing equivalents for cytochrome P450 hydroxylation of aromatic compounds, steroids, alcohols, and drugs.

Enzymes that use NADP(H) as a coenzyme[edit]

  • Adrenodoxin reductase: This enzyme is present ubiquitously in most organisms.[5] It transfers two electrons from NADPH to FAD. In vertebrates, it serves as the first enzyme in the chain of mitochondrial P450 systems that synthesize steroid hormones.[6]

Enzymes that use NADP(H) as a substrate[edit]

In 2018 and 2019, the first two reports of enzymes that catalyze the removal of the 2' phosphate of NADP(H) in eukaryotes emerged. First, the cytoplasmic protein MESH1[7], then the mitochondrial protein Nocturnin[8] where reported.


  1. ^ Hanukoglu I, Rapoport R (Feb–May 1995). "Routes and regulation of NADPH production in steroidogenic mitochondria". Endocrine Research. 21 (1–2): 231–41. doi:10.3109/07435809509030439. PMID 7588385.
  2. ^ Palmer, Michael. "10.4.3 Supply of NADPH for fatty acid synthesis". Metabolism Course Notes. Archived from the original on 6 June 2013. Retrieved 6 April 2012.
  3. ^ Rush GF, Gorski JR, Ripple MG, Sowinski J, Bugelski P, Hewitt WR (May 1985). "Organic hydroperoxide-induced lipid peroxidation and cell death in isolated hepatocytes". Toxicology and Applied Pharmacology. 78 (3): 473–83. doi:10.1016/0041-008X(85)90255-8. PMID 4049396.
  4. ^ Ogawa K, Suzuki K, Okutsu M, Yamazaki K, Shinkai S (October 2008). "The association of elevated reactive oxygen species levels from neutrophils with low-grade inflammation in the elderly". Immunity & Ageing. 5: 13. doi:10.1186/1742-4933-5-13. PMC 2582223. PMID 18950479.
  5. ^ Hanukoglu I (2017). "Conservation of the Enzyme-Coenzyme Interfaces in FAD and NADP Binding Adrenodoxin Reductase-A Ubiquitous Enzyme". Journal of Molecular Evolution. 85 (5): 205–218. doi:10.1007/s00239-017-9821-9. PMID 29177972.
  6. ^ Hanukoglu I (Dec 1992). "Steroidogenic enzymes: structure, function, and role in regulation of steroid hormone biosynthesis". The Journal of Steroid Biochemistry and Molecular Biology. 43 (8): 779–804. doi:10.1016/0960-0760(92)90307-5. PMID 22217824.
  7. ^ Ding CKC, Rose J, Wu J, Sun T, Chen KY, Chen PH, Xu E, Tian S, Akinwuntan J, Guan Z, Zhou P, Chi JTA (2018). "Mammalian stringent-like response mediated by the cytosolic NADPH phosphatase MESH1". bioRxiv. doi:10.1101/325266.
  8. ^ Estrella MA, Du J, Chen L, Rath S, Prangley E, Chitrakar A, Aoki T, Schedl P, Rabinowitz J, Korennykh A (2019). "The Metabolites NADP+ and NADPH are the Targets of the Circadian Protein Nocturnin (Curled)". bioRxiv. doi:10.1101/534560.