Catalyzes the hydrolysis of acyl-CoAs into free fatty acids and coenzyme A (CoASH), regulating their respective intracellular levels (Probable). Preferentially hydrolyzes palmitoyl-CoA, but has a broad specificity acting on other fatty acyl-CoAs with chain-lengths of C8-C18 (Probable). May play an important physiological function in brain (Probable). H2O + hexadecanoyl-CoA = CoA + H(+) + hexadecanoate dodecanoyl-CoA + H2O = CoA + dodecanoate + H(+) H2O + tetradecanoyl-CoA = CoA + H(+) + tetradecanoate decanoyl-CoA + H2O = CoA + decanoate + H(+) H2O + octanoyl-CoA = CoA + H(+) + octanoate H2O + octadecanoyl-CoA = CoA + H(+) + octadecanoate (9Z)-octadecenoyl-CoA + H2O = (9Z)-octadecenoate + CoA + H(+) Lipid metabolism; fatty acid metabolism. Homohexamer. Widely expressed with highest levels in brain. High levels also found in thymus, large intestine and testis. Negligible in muscle and adipose tissue. In the central and peripheral nervous systems, displays a predominantly neuronal localization with highest expression in cell bodies and neurites. Detected in the brain as early as embryonic day (E) 11.5. The level was low until 12.5 dpc, but promptly elevated to a peak 7 days after birth. Thereafter, it declined somewhat and reached a steady-state level in adulthood. These changes in BACH expression were approximately reflected in the palmitoyl-CoA hydrolyzing activity in the developing mouse brain, and the time course was quite similar to that of microtubule-associated protein 2 (MAP2) expression. Induced during embryogenesis in association with neuronal differentiation, and persists after terminal differentiation into neurons in postnatal stages, resulting in the constitutive high expression of BACH in the adult brain in a neuron-specific manner. Up-Regulated in activated macrophages. Both HotDog ACOT-type hydrolase domains are required for efficient activity. Major isoform.