The enzyme encoded by this gene is an Arylesterase that mainly hydrolyzes Paroxon to produce p-Nitrophenol. Paroxon is an organophosphorus anticholinesterase compound that is produced in vivo by oxidation of the insecticide parathion. Polymorphisms in this gene are a risk factor in coronary artery disease. The gene is found in a cluster of three related paraoxonase genes at 7q21.3.Synonyms: A-esterase 1, Aromatic esterase 1, EC=3.1.1.2, EC=3.1.8.1, K-45, PON, PON 1, PON-1, Serum aryldialkylphosphatase 1, Serum paraoxonase/arylesterase 1