The enzyme 3-hydroxyisobutyryl-CoA hydrolase (EC 3.1.2.4) catalyzes the reaction
The enzyme characterised from pig heart and Phaeodactylum tricornutum hydrolyses 3-hydroxy-2-methylpropanoyl-CoA to coenzyme A and the acid, 3-hydroxyisobutyric acid, which forms the thioester in the starting material. The reaction is part of a sequence that breaks down the amino acids valine and isoleucine. Deficiency of the enzyme in humans can cause a rare disease with three subtypes.
This enzyme is a hydrolase, specifically one acting on thioester bonds. The systematic name is 3-hydroxy-2-methylpropanoyl-CoA hydrolase. Other names in common use include 3-hydroxy-isobutyryl CoA hydrolase, and HIB CoA deacylase. 3-hydroxyisobutyryl-CoA hydrolase is encoded by HIBCH gene.
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