Microsomal arylacetamide deacetylase competes against the activity of cytosolic arylamine N-acetyltransferase, which catalyzes one of the initial biotransformation pathways for arylamine and heterocyclic amine carcinogens. Arylacetamide deacetylation is an important enzyme activity in the metabolic activation of arylamine substrates to ultimate carcinogens. Displays major serine hydrolase activity in liver microsomes. Hydrolyzes also flutamide, which is an antiandrogen drug used for the treatment of prostate cancer that occasionally causes severe hepatotoxicity. Displays cellular triglyceride lipase activity in liver. Increases intracellular fatty acids derived from hydrolysis of newly formed triglyceride stores.