This family consists of arylesterases (Also known as serum paraoxonase) EC:3.1.1.2. These enzymes hydrolyse organophosphorus esters such as paraoxon and are found in the liver and blood. They confer resistance to organophosphate toxicity [1]. Human arylesterase (PON1) Swiss:P27169 is associated with HDL and may protect against LDL oxidation [2].

1: Purification and characterization of paraoxon hydrolase from rat liver. Rodrigo L, Gil F, Hernandez AF, Marina A, Vazquez J, Pla A; Biochem J 1997;321:595-601. PMID:9032442

2: The human serum paraoxonase/arylesterase gene (PON1) is one member of a multigene family. Primo-Parmo SL, Sorenson RC, Teiber J, La Du BN; Genomics 1996;33:498-507. PMID:8661009