PLA2G4E and PLAAT family enzymes (in human, PLAAT-1– 5; in mice, PLAAT-1, −3, and −5) transfer a fatty acyl chain at the sn-1 position of PCs to the free amino nitrogen of PEs to produce NAPEs. NAPEs are directly converted to NAEs by NAPE-PLD. The conversion of NAPEs to NAEs is also mediated by multiple metabolic enzymes including ABHD4. Glycerophosphodiesterase (GDE) family enzymes hydrolyze lyso-NAPEs or GP-NAEs to NAEs. NAEs are degraded by FAAH/FAAH2 and NAAA. Serine hydrolases and non-serine hydrolases are shown in blue and gray, respectively.