metabolic pathway of cofactors, vitamins, nutrients nicotinamide adenine dinucleotide metabolic pathway 2016-06-01T13:58:17Z NAD metabolic pathway PW:0002580 SMP:00124 SMP:00129 Those metabolic reactions involved in the synthesis and utilization of nicotinamide adenine dinucleotide (NAD). There are several routes leading to NAD biosynthesis from various sources. NAD, in addition to its well known role as a cofactor in redox reactions, also serves as a substrate for several classes of enzymes. pathway vpetri