Oleoyl ACP Hydrolase (OLAH)

In fatty acid biosynthesis chain termination and release of the free fatty acid product is achieved by hydrolysis of the thio ester by a thioesterase I, a component of the fatty acid synthetase complex. The chain length of the released fatty acid is usually C16. However, in the mammary glands of non-ruminant mammals, and in the uropygial gland of certain waterfowl there exists a second thioesterase which releases medium-chain length fatty acids (C8 to C2)

Thioesterases are enzymes which belong to the Esterase family. Esterases, in turn, are one type of the several hydrolases known.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.