Degrades bioactive fatty acid amides to their corresponding acids, with the following preference: N-palmitoylethanolamine > N-myristoylethanolamine > N-stearoylethanolamine > N-oleoylethanolamine > N-linoleoylethanolamine > N-arachidonoylethanolamine. H2O + N-hexadecanoylethanolamine = ethanolamine + hexadecanoate H2O + N-(long-chain fatty acyl)ethanolamine = a long-chain fatty acid + ethanolamine H2O + N-dodecanoylethanolamine = dodecanoate + ethanolamine H2O + N-tetradecanoylethanolamine = ethanolamine + tetradecanoate an N-acylsphing-4-enine + H2O = a fatty acid + sphing-4-enine H2O + N-hexadecanoylsphing-4-enine = hexadecanoate + sphing-4-enine H2O + N-dodecanoylsphing-4-enine = dodecanoate + sphing-4-enine Lipid metabolism; fatty acid metabolism. Heterodimer of an alpha and a beta subunit, produced by autocatalytic cleavage. N-glycosylated (PubMed:30301806). Tunicamycin treatment causes a reduction in specific activity against N-palmitoylethanolamine (By similarity). Autoproteolytic cleavage at pH 4.5 gives rise to the alpha and beta subunit (PubMed:30301806). Cleavage gives rise to a conformation change that activates the enzyme. The same catalytic Cys residue mediates the autoproteolytic cleavage and subsequent hydrolysis of lipid substrates (By similarity). Belongs to the acid ceramidase family.