What Is NAD+?
NAD+ (nicotinamide adenine dinucleotide) is a dinucleotide coenzyme found in every living cell, where it functions as a central carrier of electrons in metabolic redox reactions. The molecule cycles between an oxidized state (NAD+) and a reduced state (NADH), shuttling electrons through the pathways that convert nutrients into usable cellular energy. Beyond electron transfer, NAD+ serves as a direct substrate for two major enzyme families studied extensively in cellular biology: sirtuins, which regulate gene expression and mitochondrial activity through protein deacetylation, and poly(ADP-ribose) polymerases (PARPs), which consume NAD+ to repair damaged DNA. This dual role as both an energy carrier and an enzyme substrate has made NAD+ one of the most studied molecules in cellular metabolism research, with applications spanning mitochondrial biology, genomic stability, and models of cellular aging. At Azoth, NAD+ research material is manufactured to a high purity standard and supplied exclusively for laboratory and analytical research applications.
Molecular Profile
CAS Number: 53-84-9 Molecular Formula: C21H27N7O14P2 Molecular Weight: 663.43 g/mol PubChem CID: 925 Synonyms: beta-NAD, Diphosphopyridine Nucleotide (DPN), Coenzyme I
How Does NAD+ Work? Several Mechanisms Explored
Redox Cycling and Cellular Energy Metabolism NAD+ functions as the primary electron acceptor in glycolysis, the citric acid cycle, and oxidative phosphorylation. As it accepts electrons from these pathways, NAD+ is converted to NADH, which then donates those electrons to the electron transport chain to drive ATP synthesis. This redox cycle places NAD+ at the center of cellular energy production, and the NAD+/NADH ratio is widely used in research models as a marker of mitochondrial and metabolic status.
Sirtuin Activation and Mitochondrial Signaling NAD+ is an obligate cosubstrate for the sirtuin family of enzymes (SIRT1 through SIRT7), which use it to remove acetyl groups from histones and other regulatory proteins. In aged mouse models, a decline in nuclear NAD+ was linked to a pseudohypoxic state that disrupted communication between the nucleus and mitochondria, reducing expression of mitochondrially encoded oxidative phosphorylation subunits. Raising NAD+ levels in these animals restored mitochondrial gene expression in a SIRT1-dependent manner.
PARP-Mediated DNA Repair Poly(ADP-ribose) polymerases, particularly PARP1, consume NAD+ as a substrate when repairing single- and double-strand DNA breaks. Because sirtuins and PARPs draw from the same intracellular NAD+ pool, research has examined how NAD+ availability shapes the balance between DNA repair capacity and mitochondrial function, with reduced NAD+ pools associated with increased PARylation in disease models.
NAD+ Salvage Pathway and NAMPT Intracellular NAD+ levels are maintained through the salvage pathway, in which nicotinamide phosphoribosyltransferase (NAMPT) converts nicotinamide back into NAD+ precursors. Research models have shown that NAMPT activity and NAD+ salvage capacity decline with age and in models of neuromuscular dysfunction, making the salvage pathway a focus of ongoing preclinical investigation.





