Sirtuin - Types

Types

The first sirtuin was identified in yeast (a lower eukaryote) and named sir2. In more complex mammals, there are seven known enzymes that act in cellular regulation, as sir2 does in yeast. These genes are designated as belonging to different classes, depending on their amino acid sequence structure. Several Gram positive prokaryotes as well as the Gram negative hyperthermophilic bacterium Thermotoga maritima possess sirtuins that are intermediate in sequence between classes. These are placed in class U.

Class Subclass Species Intracellular
location		 Activity Function
Bacteria Yeast Mouse Human
I a Sir2 or Sir2p,
Hst1 or Hst1p		 Sirt1 SIRT1 nucleus, cytoplasm deacetylase metabolism
inflammation
b Hst2 or Hst2p Sirt2 SIRT2 cytoplasm deacetylase cell cycle,
tumorigenesis
Sirt3 SIRT3 nucleus and
mitochondria		 deacetylase metabolism
c Hst3 or Hst3p,
Hst4 or Hst4p
II Sirt4 SIRT4 mitochondria ADP-ribosyl
transferase		 insulin secretion
III Sirt5 SIRT5 mitochondria demalonylase, desuccinylase and deacetylase ammonia detoxification
IV a Sirt6 SIRT6 nucleus Demyristoylase, depalmitoylase, ADP-ribosyl
transferase and deacetylase		 DNA repair,
metabolism,
TNF secretion
b Sirt7 SIRT7 nucleolus deacetylase rDNA
transcription
U cobB regulation of
acetyl-CoA synthetase		 metabolism

Sirtuin list based on North/Verdin diagram.

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