– Abhydrolase domain containing 4 (ABHD4), also known as alpha/beta-hydrolase 4 (ABH4) , or lyso-N-acylphosphatidylethanolamine lipase, which belongs to the ABHD4/ABHD5 subfamily of peptidase S33 family. Abhydrolase domain containing (ABHD) gene was a small group belongs to alpha/beta hydrolase superfamily. Known members of this group are all found to be involved in important biochemical processes and related to various diseases. The alpha/beta-hydrolase 4 (ABH4) is a lysophospholipase/phospholipase B that selectively hydrolyzes N-acyl phosphatidylethanolamines (NAPEs) and lysoNAPEs. ABH4 accepts lysoNAPEs bearing both saturated and polyunsaturated N-acyl chains as substrates and displays a distribution that closely mirrors lysoNAPE-lipase activity in mouse tissues. The existence of an NAPE-PLD-independent route for NAE biosynthesis and suggest that ABH4 plays a role in this metabolic pathway by acting as a (lyso)NAPE-selective lipase.