Paraoxonase 3 (PON3)

Members of the paraoxonase (EC 3.1.1.2) gene family, such as PON3, encode high density lipoprotein (HDL)-related glycoproteins with multienzymatic properties. (Lu et al., 2006).Lu et al. (2006) cloned PON3 from a fetal liver cDNA library. The deduced mature protein has 354 amino acids and a calculated molecular mass of 39.6 kD. It contains 3 cysteines that are conserved in PON1 and PON2. Cys41 and cys351 are predicted to form an intramolecular disulfide bond, and cys283 is predicted to be involved in antioxidant activity. Using nondenaturing PAGE, Draganov et al. (2005) observed native recombinant PON3 at an apparent molecular mass of 94.9 kD, suggesting that it probably forms dimers. Glycosidase treatment of human serum PON3 suggested that the secreted form of PON3 contains complex carbohydrates.