nicotinamide
(nik‵ŏ-tiē'nă-mīd‵, tin'ă 
)
[nicotine + amide]
A basic amide that is a member of the vitamin B complex, used in the prophylaxis and treatment of pellagra. SYN: niacinamide.
ABBR: NAD
An enzyme important in accepting electrons in the course of metabolic reactions. In its oxidized form, NAD+ gives up its electron and is converted to the reduced form, NADH.SYN: V factor.n. adenine dinucleotide-dehydrogenase
SEE: nicotinamide adenine dinucleotide phosphate.
n. adenine dinucleotide phosphate
ABBR: NADP
A coenzyme that contains adenosine, nicotinamide, and phosphoric acid. When in its oxidized form (NADP+), it serves as an electron carrier in catabolic and anabolic reactions. In its reduced form (NADPH or NADPH-diaphorase), it is important in reducing the ferric iron (Fe+++) to its ferrous (Fe++) form, thus converting methemoglobin (which is unable to transport oxygen) to hemoglobin (which can transport oxygen). Deficiency of NADPH-diaphorase causes congenital methemoglobinemia. SYN: methemoglobin reductase.