Table 1.

Localization, substrates, functions and enzyme activities of different sirtuins

Sirtuin	Subcellular localization	High tissue expression	Main substrates	Functions	Enzyme activity
SIRT1	Nuclear and cytosolic	Brain, skeletal muscle, heart, kidney and uterus	Histones H1, H3 and H4 Transcripton factors p53, FOXO family, Ku70,p300, NF- κB, PGC-1α, PPAR-γ, UCP2 Acetyl-CoA synthetase 1	Cell survival, lifespan regulation, metabolism regulation, inflammation, oxidative stress response	NAD+-dependent deacetylase
SIRT2	Cytosolic and nuclear	Brain	α-tubulin	Cell cycle regulation, nervous system development	NAD+-dependent deacetylase
SIRT3	Mitochondrial, nuclear and cytosolic	Brain, heart, liver, kidney and brown adipose tissue	Acetyl-CoA synthetase 2 Isocitrate dehydrogenase 2 Ku70, FOXO 3a, MnSOD, Mitochondrial ribosomal protein L10 Long-chain acyl-CoA deshydrogenase 3-Hydroxy-3-Methylglutaryl CoA synthase 2 Succinate deshydrogenase, NADH:quinone oxidoreductase	Regulation of mitochondrial metabolism	NAD+-dependent deacetylase
SIRT4	Mitochondrial	Pancreatic β-cells, brain, liver, kidney and heart	Glutamate dehydrogenase	Regulation of mitochondrial metabolism,	ADP-ribosyl transferase
SIRT5	Mitochondrial	Brain, testis, heart muscle and lymphoblast	Cytochrome c Carbamoyl phosphate synthetase 1,	Apoptosis	NAD+-dependent deacetylase Desuccinylase Demalonylase
SIRT6	Nuclear, associated to heterochromatin	Muscle, brain, heart, ovary and bone cells (absent in bone marrow)	Histone H3 TNF-α PAPR1	Genome stability, DNA repair	NAD+-dependent deacetylase ADP-ribosyl transferase
SIRT7	Nucleolar	Peripheral blood cells, CD33+ myeloid bone marrow precursor cells	RNA polymerase I p53	Regulation of rRNA transcription, cell cycle regulation	NAD+-dependent deacetylase