Acyl-CoA thioesterases are a group of enzymes that catalyze the hydrolysis of acyl-CoAs to the free fatty acid and coenzyme A (CoASH), providing the potential to regulate intracellular levels of acyl-CoAs, free fatty acids and CoASH. Has an acyl-CoA thioesterase activity towards the long chain fatty acyl-CoA thioester palmitoyl-CoA (hexadecanoyl-CoA; C16:0-CoA). Displays a substrate preference for fatty acyl-CoAs with chain-lengths C12-C18. H2O + hexadecanoyl-CoA = CoA + H(+) + hexadecanoate dodecanoyl-CoA + H2O = CoA + dodecanoate + H(+) H2O + tetradecanoyl-CoA = CoA + H(+) + tetradecanoate H2O + octadecanoyl-CoA = CoA + H(+) + octadecanoate a beta-lactam + H2O = a substituted beta-amino acid Binds 2 Zn(2+) ions per subunit. Belongs to the metallo-beta-lactamase superfamily. Glyoxalase II family.