FIG 1.

Salvage pathway for NAD⁺. The moieties used for the salvage synthesis of NAD⁺ are represented with different colors (pyridine, yellow; ribose, green; amino group, red). The de novo biosynthesis pathway for NAD⁺ is also shown with dashed lines. NAD, NAD⁺; NAM, nicotinamide; NA, nicotinate; ADPR, ADP-ribose; R5P, ribose 5-phosphate; PRPP, phosphoribosyl diphosphate; NaMN, nicotinate mononucleotide; NaAD, nicotinate adenine dinucleotide; QA, quinolinate; NAMase, nicotinamidase; NaMAT, nicotinate mononucleotide adenylyltransferase; NaPRT, nicotinate phosphoribosyltransferase; ADPRP, ADPR pyrophosphatase; RPK, ribose-phosphate pyrophosphokinase; NADS, NAD⁺ synthase.