Hydrolysis of the acetyl group from the 1-alkyl-2-acetyl and 1-alkyl-3-acetyl substrates occurs at apparently identical rates. The enzyme from Erlich ascites cells is membrane-bound. It differs from lipoprotein lipase (EC?3.1.1.34) since 1,2-diacetyl-sn-glycerols are not substrates. It also differs from EC?3.1.1.47?(1-acetyl-2-alkyl-glycerophosphocholine esterase).