3-Hydroxyisobutyryl Coenzyme A Hydrolase (HIBCH)

Beta-hydroxyisobutyryl-CoA hydrolase (EC 3.1.2.4) is responsible for the specific hydrolysis of HIBYL-CoA, a valine catabolite, as well as the hydrolysis of beta-hydroxypropionyl-CoA, an intermediate in a minor pathway of propionate metabolism.

The protein contains a 28-amino acid mitochondrial leader sequence and shows significant homology with the enoyl-CoA hydratase/isomerase enzyme family. Northern blot analysis revealed expression of an approximately 2-kb transcript, with highest expression in skeletal muscle, followed by liver, heart, kidney, and brain. Western blot analysis also demonstrated tissue-specific expression but with quantitatively different tissue distribution that was most apparent in soleus muscle.