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Nicotinamide adenine dinucleotide phosphate

|Section2={{Chembox Properties | C=21 | H=29 | N=7 | O=17 | P=3 | Appearance = | Density = | MeltingPt = | BoilingPt = }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }} Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as lipid and nucleic acid synthesis, 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

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. It is used to help turn the carbon dioxide into glucose. It is also needed in the reduction of nitrate into ammonia for plant assimilation in nitrogen cycle.

In animals

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. The isocitrate dehydrogenase mechanism appears to be the major source of NADPH in fat and possibly also liver cells. Also, in mitochondria, NADH kinase produces NADPH and ADP, using NADH and ATP as substrates.

Function

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). NADPH is also used for anabolic pathways, such as lipid synthesis, 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. It is the source of reducing equivalents for cytochrome P450 hydroxylation of aromatic compounds, steroids, alcohols, and drugs.
"green air" © 2007 - Ingo Malchow, Webdesign Neustrelitz
This article based upon the http://en.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide_phosphate, the free encyclopaedia Wikipedia and is licensed under the GNU Free Documentation License.
Further informations available on the list of authors and history: http://en.wikipedia.org/w/index.php?title=Nicotinamide_adenine_dinucleotide_phosphate&action=history
presented by: Ingo Malchow, Mirower Bogen 22, 17235 Neustrelitz, Germany