An enzyme which catalyzes the Hydrolysis of an aryl-dialkyl phosphate to form dialkyl phosphate and an aryl alcohol. It can hydrolyze a broad spectrum of organophosphate substrates and a number of aromatic carboxylic acid esters. It may also mediate an enzymatic protection of Low Density Lipoproteins against oxidative modification and the consequent series of events leading to ATHEROMA formation. The enzyme was previously regarded to be identical with Arylesterase (EC