paraoxonase-1 (pon1) is a serum hdl-bound enzyme that hydrolyzes a number of aromatic carboxylic acid esters including lipid peroxides, preventing ldl oxidation. systemic lupus erythematosus (sle) patients are at greater risk of oxidative stress, which is associated with abnormal plasma lipid metabolism. in this study, association of pon-55 polymorphism with serum arylesterase (are) activities,...

human serum paraoxonase (hupon1:   ec 3.1.8.1), a calcium-dependent esterase, is synthesized in the liver and   widely distributed in tissues including liver, kidney, intestine, and serum,   where it is associated exclusively with high-density lipoprotein.  human paraoxonase-1 plays an important role   in prevention of atherosclerosis and also protection against organophosphate-induced   neurot...

BACKGROUND Recently another member of the paraoxonase gene family designated paraoxonase-2 has been identified. Paraoxonase-2 has antioxidant properties similar to paraoxonase-1 and paraoxonase-3. However, in contrast to paraoxonase-1 and paraoxonase-3, paraoxonase-2 is not associated with high-density lipoprotein and may only exert its antioxidant function at the cellular level. METHODS We a...

BACKGROUND Apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 are antioxidant and anti-atherosclerotic structural high-density lipoprotein proteins that are mainly synthesized by the liver. No study has ever been performed to specifically examine the effects of caffeine on paraoxonase enzymes and on liver apolipoprotein A-1 protein levels. AIMS To investigate the dose-dependent effects of ca...

human serum paraoxonase (pon) associated with high density lipoprotein (hdl) , has been postulated to have a role in protecting low-density lipoprotein (ldl) against oxidative damage, which has led to the proposal that pon is an anti-atherogenic and anti-inflammatory enzyme. it has genetic polymorphism at the 191 (r ->q) and two alloenzymes a and b and three phenotypes a, b, and ab. we examined...

OBJECTIVE The purpose of this study was to analyze the consequences of HDL oxidation for paraoxonase-1 metabolism and function. METHODS AND RESULTS HDL was oxidized with AAPH, copper ions, and hypochlorite. Secretion studies were performed using human paraoxonase-1-transfected cells lines and primary rat hepatocytes. Stability studies were performed with recombinant paraoxonase. Conditioned m...

To determine the causes responsible for a preferential decrease of paraoxonase activity, which has been observed in the serum of patients with cardiovascular diseases, the inactivation or inhibition of paraoxonase 1 (PON1) by various endogenous factors was examined using paraoxon or phenyl acetate as a substrate. When purified PON1 was incubated with various endogenous oxidants or aldehydes, th...

There are many evidences that human serum paraoxonase activity modifies plasma lipid profile and paraoxonase has an antiatherogenic property. Non-selective beta-blockers affect plasma lipid profile too, but they have atherogenic property when patients take these drugs in long term. In this study the effect of propranolol, a non-selective beta-blocker, on paraoxonase activity was investigated. L...