a coenzyme present in most living cells and derived from the B vitamin nicotinic acid; serves as a reductant in various metabolic processes
An important coenzyme, functioning as a hydrogen carrier in a wide range of redox reactions; the H is carried on the nicotinamide residue. The oxidized form of the coenzyme is written NAD+, the reduced form as NADH (or NADH+H+).
Nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+) are two important coenzymes found in cells. They play key roles as carriers of electrons in the transfer of reduction potential.