Paraoxonases (PON1, PON2, PON3) are calcium-dependent esterases, involved in lipid metabolism, oxidative stress control, and protection from organo-phosphates. PON1 circulates bound to HDL, exhibiting arylesterase, lactonase, and organophosphatase activity. PON2 is an intracellular, membrane- associated enzyme (ER, mitochondria, nuclear envelope) and PON3 is HDL-associated like PON1 but less abundant and less well characterized. All three share structural homology but differ in tissue distribution, substrate spectrum, and whether they are secreted or intracellular. PON1 hydrolyses lipid peroxides in LDL and HDL, reduces oxidized phospholipids, and promotes HDL-mediated cholesterol efflux from macrophages. PON1 improves insulin sensitivity, upregulating GLUT4 in muscle independently of insulin receptor signaling. AkrivisBio’s Paraoxonase-1 Activity Assay, designed to test serum/plasma samples for PON1 activity, is a simple, sensitive measurement procedure with a sensitivity below 2 microUnits per sample.
