Nicotinamide Adenine Dinucleotide-Related Enzymes (None)

Nicotinamide adenine dinucleotide (NAD) and its related enzymes are central to cellular metabolism, energy production, and signaling in all living cells. NAD exists in two forms: the oxidized form (NAD⁺) and the reduced form (NADH). These molecules act as essential cofactors for a wide range of enzymes, particularly those involved in redox reactions. NAD-related enzymes primarily function as oxidoreductases—catalyzing electron transfer during metabolic processes such as glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation. Several enzyme families use NAD⁺ as a substrate, including Sirtuins (protein deacetylases), PARPs (Poly(ADP-ribose) polymerases), and CD38/CD157/SARM1 (glycohydrolases). Declining levels of cellular/nuclear/mitchondrial pools of these cofactors are linked with aging processes and age-related diseases.