Catalyzes the hydrolysis of endogenous amidated lipids like the sleep-inducing lipid oleamide ((9Z)-octadecenamide), the endocannabinoid anandamide (N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-ethanolamine), as well as other fatty amides, to their corresponding fatty acids, thereby regulating the signaling functions of these molecules (PubMed:17015445, PubMed:19926788). Hydrolyzes monounsaturated substrate anandamide preferentially as compared to polyunsaturated substrates. H2O + N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-ethanolamine = (5Z,8Z,11Z,14Z)-eicosatetraenoate + ethanolamine (9Z)-octadecenamide + H2O = (9Z)-octadecenoate + NH4(+) H2O + N-(9Z-octadecenoyl) ethanolamine = (9Z)-octadecenoate + ethanolamine H2O + N-hexadecanoylethanolamine = ethanolamine + hexadecanoate Inhibited by O-aryl carbamates and alpha-keto heterocytes. Optimum pH is around 9.0. Homodimer. Expressed in kidney, liver, lung, prostate, heart and ovary. Belongs to the amidase family.