SirT3(Sirtuin 3) is a member of the sirtuin family of class III histone deacetylases, homologs to the yeast Sir2 protein. SirT3 plays a crucial role in mitochondrial function as a NAD-dependent deacetylase, which is essential for regulating metabolic processes and maintaining cellular homeostasis. By deacetylating specific lysine residues on target proteins within the mitochondria, SirT3 modulates various pathways, including those involved in energy metabolism and oxidative stress response. This regulation is vital for cellular adaptation to stress and has implications in aging and age-related diseases, making SirT3 a significant focus of research in the context of metabolic disorders and mitochondrial dysfunction. SirT3 is processed by mitochondrial processing peptidase to yield its active form, highlighting the importance of post-translational modifications in functional activity.