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:9122178, PubMed:9299394, PubMed:9790682, PubMed:10526230, PubMed:11128635, PubMed:15533037, PubMed:17649977). Hydrolyzes polyunsaturated substrate anandamide preferentially as compared to monounsaturated substrates (PubMed:9122178, PubMed:11128635). It can also catalyze the hydrolysis of the endocannabinoid 2-arachidonoylglycerol (2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-glycerol) (PubMed:10526230, PubMed:15533037, PubMed:17649977). FAAH cooperates with PM20D1 in the hydrolysis of amino acid-conjugated fatty acids such as N-fatty acyl glycine and N-fatty acyl-L-serine, thereby acting as a physiological regulator of specific subsets of intracellular, but not of extracellular, N-fatty acyl amino acids (By similarity). H2O + N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-ethanolamine = (5Z,8Z,11Z,14Z)-eicosatetraenoate + ethanolamine (9Z)-octadecenamide + H2O = (9Z)-octadecenoate + NH4(+) 2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-glycerol + H2O = (5Z,8Z,11Z,14Z)-eicosatetraenoate + glycerol + H(+) (9Z,12Z,15Z)-octadecatrienamide + H2O = (9Z,12Z,15Z)-octadecatrienoate + NH4(+) (5Z,8Z,11Z,14Z)-eicosatetraenamide + H2O = (5Z,8Z,11Z,14Z)-eicosatetraenoate + NH4(+) (6Z)-octadecenamide + H2O = (6Z)-octadecenoate + NH4(+) (15Z)-tetracosenamide + H2O = (15Z)-tetracosenoate + NH4(+) (8Z,11Z,14Z)-eicosatrienamide + H2O = (8Z,11Z,14Z)-eicosatrienoate + NH4(+) (11Z,14Z,17Z)-eicosatrienamide + H2O = (11Z,14Z,17Z)-eicosatrienoate + NH4(+) (11Z,14Z)-eicosadienamide + H2O = (11Z,14Z)-eicosadienoate + NH4(+) (9Z,12Z)-octadecadienamide + H2O = (9Z,12Z)-octadecadienoate + NH4(+) H2O + tetradecamide = NH4(+) + tetradecanoate H2O + N-(9Z-octadecenoyl) ethanolamine = (9Z)-octadecenoate + ethanolamine H2O + N-(9Z-octadecenoyl)-taurine = (9Z)-octadecenoate + taurine 1-O-methyl-(5Z,8Z,11Z,14Z)-eicosatetraenoate + H2O = (5Z,8Z,11Z,14Z)-eicosatetraenoate + H(+) + methanol (11Z)-eicosenamide + H2O = (11Z)-eicosenoate + NH4(+) H2O + N-(9Z-hexadecenoyl) ethanolamine = (9Z)-hexadecenoate + ethanolamine H2O + N-octadecanoyl ethanolamine = ethanolamine + octadecanoate H2O + N-docosanoyl-ethanolamine = docosanoate + ethanolamine H2O + N-tetracosanoyl-taurine = taurine + tetracosanoate H2O + N-(15Z-tetracosenoyl)-ethanolamine = (15Z)-tetracosenoate + ethanolamine H2O + N-docosanoyl-taurine = docosanoate + taurine H2O + N-(15Z-tetracosenoyl)-taurine = (15Z)-tetracosenoate + taurine H2O + N-tricosanoyl-taurine = taurine + tricosanoate (9Z)-octadecenoate + glycine = H2O + N-(9Z-octadecenoyl)glycine H2O + N-(5Z,8Z,11Z,14Z)-eicosatetraenoyl-glycine = (5Z,8Z,11Z,14Z)-eicosatetraenoate + glycine H2O + N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-L-serine = (5Z,8Z,11Z,14Z)-eicosatetraenoate + L-serine inhibited by trifluoromethyl ketone. kcat is 7.1 sec(-1) with oleamide ((9Z)-octadecenamide) (PubMed:9790682). kcat is 28 min(-1) with 2-arachidonoylglycerol (2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-glycerol) (PubMed:17649977). kcat is 16 min(-1) with anandamide (N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-ethanolamine) (PubMed:17649977). Optimum pH is 9.5. Homodimer. Seems to be associated with the endoplasmic reticulum and/or Golgi apparatus. Found in neuronal cells throughout the CNS. Expressed in liver and brain, and to a lesser extent in spleen, lung, kidney and testes. In the CNS it accumulates progressively between embryonic day 14 and postnatal day 10, remains high until postnatal day 30, then decreases into adulthood. Belongs to the amidase family.