NAD+ biosynthetic and metabolizing enzymes

NAD+ biosynthetic and metabolizing enzymes represent a diverse group of proteins that regulate the levels and activity of nicotinamide adenine dinucleotide (NAD+), a fundamental coenzyme for cellular redox reactions and a key substrate for signaling pathways [1, 2]. This category encompasses biosynthetic enzymes such as nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD+ salvage pathway, and NAD+-consuming enzymes including poly(ADP-ribose) polymerases (PARPs), sirtuins (SIRTs), and CD38 [5, 6]. These enzymes are essential for maintaining energy metabolism, genomic stability through DNA repair, and epigenetic regulation [7, 9]. Dysregulation of this enzymatic network is a hallmark of several diseases; for instance, many cancers exhibit an addiction to NAMPT-mediated NAD+ synthesis to support rapid proliferation, while age-related decline in NAD+ is linked to neurodegeneration and metabolic disorders [8, 15, 16]. Therapeutic interventions targeting these enzymes include NAMPT inhibitors (e.g., FK866) for cancer treatment, PARP inhibitors (e.g., olaparib) for DNA repair-deficient tumors, and NAD+ precursors or sirtuin activators to combat aging and metabolic decline [4, 10, 11]. Overall, these enzymes serve as critical metabolic sensors that link the energy status of the cell to vital physiological responses.

Other names

NAD+ metabolic enzymesNAD+ metabolism enzymesNAD+ biosynthetic pathway enzymesNAD+ consuming enzymes

Drugs targeting these enzymes primarily act by modulating cellular NAD+ levels or the activity of NAD+-dependent signaling proteins. NAMPT inhibitors deplete NAD+ to induce metabolic collapse and apoptosis in cancer cells. PARP inhibitors block DNA repair, leading to synthetic lethality in BRCA-mutant cells. CD38 inhibitors prevent NAD+ degradation and modulate calcium signaling or immune responses. Conversely, NAD+ precursors and sirtuin activators aim to restore NAD+ levels to improve mitochondrial function and promote healthy aging.