cell-biology
Sirtuin
Definition
Sirtuins are a family of seven NAD+-dependent deacylase enzymes (SIRT1-SIRT7) that regulate critical cellular processes including DNA repair, mitochondrial biogenesis, inflammation, and metabolic homeostasis. SIRT1 and SIRT3 are particularly implicated in longevity pathways, as they mediate the beneficial effects of caloric restriction by deacetylating histones, transcription factors, and metabolic enzymes. Sirtuin activity is directly dependent on NAD+ availability, linking age-related NAD+ decline to reduced sirtuin function and the hallmarks of aging.