nicotinamide adenine dinucleotide phosphate

(cell and molecular biology) A coenzyme and important component of the enzymatic systems concerned with biological oxidation-reduction systems. Abbreviated NADP+ (the reduced form is abbreviated NADPH).

A coenzyme and an important component of the enzymatic systems concerned with biological oxidation-reduction systems. It is also known as NAD, triphosphopyridine nucleotide (TPN), coenzyme II, and codehydrogenase II. The compound is similar in structure and function to nicotinamide adenine dinucleotide (NAD). It differs structurally from NAD in having an additional phosphoric acid group esterified at the 2′ position of the ribose moiety of the adenylic acid portion. In biological oxidation-reduction reactions the NADP molecule becomes alternately reduced to its hydrogenated form (NADPH) and reoxidized to its initial state (see illustration). See also Coenzyme; Enzyme.

nicotinamide portion of TPNH. (b) Oxidized form of the molecule (TPN).">
Triphosphopyridine nucleotide. (a) Reduced form of the nicotinamide portion of TPNH. (b) Oxidized form of the molecule (TPN).

NADP.