Figure 1.
Scheme showing the structure of NAD+, NAD+-consuming reactions catalyzed by PARPs, sirtuins, and NAD+ glycohydrolases, and the NAD+ biosynthesis pathways.
Abbreviation for small molecules: NAM, nicotinamide; NA, nicotinic acid; NaMN, nicotinate mononucleotide; NMN, nicotinamide mononucleotide; NaAD+, nicotinate adenine dinucleotide; NR, nicotinamide riboside; Trp, tryptophan; QA, quinolinic acid.