Function: Involved in the detoxification of xenobiotics and in the activation of ester and amide prodrugs. Hydrolyzes aromatic and aliphatic esters, but has no catalytic activity toward amides or a fatty acyl-CoA ester. Hydrolyzes the methyl ester group of cocaine to form benzoylecgonine. Catalyzes the transesterification of cocaine to form cocaethylene. Displays fatty acid ethyl ester synthase activity, catalyzing the ethyl esterification of oleic acid to ethyloleate. PTM: Contains sialic acid. Cleavage of the signal sequence can occur at 2 positions, either between Trp-17 and Gly-18 or between Gly-18 and His-19. Similarity: Belongs to the type-B carboxylesterase/lipase family. Tissue specificity: Expressed predominantly in liver with lower levels in heart and lung.