Hydrolyzes the toxic metabolites of a variety of organophosphorus insecticides. Capable of hydrolyzing a broad spectrum of organophosphate substrates and lactones, and a number of aromatic carboxylic acid esters. Mediates an enzymatic protection of low density lipoproteins against oxidative modification. a phenyl acetate + H2O = a phenol + acetate + H(+) An aryl dialkyl phosphate + H2O = dialkyl phosphate + an aryl alcohol. an N-acyl-L-homoserine lactone + H2O = an N-acyl-L-homoserine + H(+) Binds 2 calcium ions per subunit. Homodimer. Interacts with CLU. Plasma. Associated with HDL. Glycosylated. The signal sequence is not cleaved. The preferential association of PON1 with HDL is mediated in part by its signal peptide, by binding phospholipids directly, rather than binding apo AI. The retained signal peptide may allow transfer of the protein between phospholipid surfaces. Belongs to the paraoxonase family.