Nicotinamide adenine dinucleotide phosphate

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.