Sirtuins

Sirtuins are a family of seven NAD+-dependent enzymes (SIRT1–SIRT7) that deacetylate or otherwise modify proteins involved in metabolism, DNA repair, mitochondrial function, and stress response. Their activity depends on cellular NAD+ availability, linking nutrient status to gene regulation. Sirtuins are implicated in caloric restriction's longevity effects, though direct lifespan extension by sirtuin activators in mammals remains debated. SIRT1, SIRT3, and SIRT6 receive the most aging-related research attention.