Biochemical functions of vitamin PP are defined by participation of nicotine amide in construction of nicotine amide coenzymes of NAD and NADP (nicotinamide adenine dinucleotide phosphate), catalyzing oxidative-reduction reactions in a cell, as shown on Fig. 2 on the example of transition from NAD+ to NADN. About 300 enzymes, functioning with the participation of oxidized and reduced forms of NAD and NADP, are known (Zhusupova, 2009).