(= nicotinamide adenine dinucleotide; NAD+ ; formerly DPN) Coenzyme in which the nicotine ring undergoes cyclic reduction to NADH and oxidation to NAD. Acts as a diffusible substrate for dehydrogenases etc. NADH+ is one source of reducing equivalents for the electron transport chain. NAD is of special interest as the source of ADP-ribose (see ADP-ribosylation).
(Nicotinamide adenine dinucleotide) The oxisided form of the coenzyme of an enzyme involved in respiration. NADH2 is the reduced form of the coenzyme. NAD was formerly called DPN (diphosphorpyridine nucleotide).