Thioesterases exhibit Esterase activity (splitting of an ester into acid and alcohol, in the presence of water) specifically at a thiol group.
Thioesterases or thiolester hydrolases are identified as members of E.C.3.1.2.
The thioesterase activity is performed by members of the acyl-CoA thioesterase (ACOT) family. The regulatory role of ACOT in fatty acid metabolism depends on their substrate specificity, tissue expression and subcellular localization. For example, deactivation of fatty acids at the ER may traffic fatty acids away from pathways associated with the ER membrane, such as glycerolipid biosynthesis. Two structurally different ACOT types lead to a similar enzymatic activity in vitro, dividing the family into type I and type II ACOTs .
Type I ACOTs (ACOT1–6) contain the α/β-hydrolase domain, which is also present in many lipases and esterases .
Type II ACOTs (ACOT7–15) have a characteristic structural motif called the ‘Hotdog fold’ domain .
Ubiquitin thiolesterase is a well-known example, whose structure has been analyzed.
Humans genes which encode thioesterases include:
- Steensels S, Ersoy B. Fatty acid activation in thermogenic adipose tissue. Biochim Biophys Acta, 2018 May 21.
- Brocker, C; Carpenter, C; Nebert, DW; Vasiliou, V (Aug 2010). "Evolutionary divergence and functions of the human acyl-CoA thioesterase gene ( ACOT ) family". Human Genomics. 4 (6): 411–20. doi:10.1186/1479-7364-4-6-411. PMC 3525216. PMID 20846931.