The sirtuins (SIRTs) represent a distinct class of trichostatin A-insensitive lysyl-deacetylases (class III HDACs) and have been shown to catalyze a reaction that couples lysine deacetylation to the formation of nicotinamide and O-acetyl-ADP-ribose from NAD+ and the abstracted acetyl group.1,2,3 There are seven human SIRTs, which have been designated SIRT 1-7.4 SIRT3, is a mitochondrial protein, with its N-terminal 25 amino acid residues responsible for its localization.5,6 Synthesized as an enzymatically inactive protein, human SIRT3 is activated by a matrix-processing peptidase.6 Recently, it was demonstrated that SIRT3 is translocated to the mitochondria from the nucleus during cellular stress or by the overexpression of SIRT3 itself.7 In mice, caloric restriction up-regulates SIRT3 expression levels in white and brown adipose tissue (WAT & BAT). Cold exposure also induces SIRT3 in brown adipose tissue (BAT).8 The constitutive expression of SIRT3 promotes the expression of PGC-1a, UCP1, and other genes involved in mitochondrial functions, indicating that SIRT3 modulates adaptive thermogenesis in BAT.8WARNING This product is not for human or veterinary use.
