Characterization of partially purified preparations of human serum paraoxonase

Kenta Nakamura
University of California, Los Angeles

Low density lipoprotein (LDL) oxidation and high density lipoprotein (HDL) oxidative protection have been widely reported to be key aspects of atherogenesis. Oxidation products of the arachidonic acid containing phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC) found in LDL membranes have been shown to emulate the physiological properties of mildly modified LDL (MM-LDL) and are thus logical targets of HDL's antioxidant properties. Several lines of evidence have shown that the protective effects of HDL are partly conferred by the HDL associated arylesterase, human serum paraoxonase 1 (PON1), suggesting that PON1 is an anti-atherogenic enzyme. In the present study, we aim to elucidate the specific substrate and mechanism of PON-mediated oxidative protection.