Silent information regulator (Sir2)-like family deacetylases (also known as sirtuins) are highly conserved proteins and have important roles in the regulation of metabolism, inflammation, cellular survival growth and differentiation. Sirtuins, including SIRT1-7, are human homologs of yeast Sir2p. Sirtuins are NAD-dependent protein ADP-ribosyl transferase which catalyzes the transfer of ADP-ribosyl groups onto target proteins, including mitochondrial GLUD1. SIRT4 localizes to mitochondria, inhibits glutamate dehydrogenase (GLUD1), and may involve in the regulation of insulin secretion.