engleski

A polymorphism of the paraoxonase gene associated with cardiovascular disease

Paraoxonase (PON), a Ca+2 dependent enzyme, is a high density lipoprotein (HDL) associated esterase hydrolyzing paraoxon. Although the physiologic substrate of PON1 is unknown, a protective role against the oxidative degradation of LDL has been attributed to it. Many studies have suggested that the existence of a genetic polymorphism of PON1 gene involving Gln-to-Arg interchange at position 192 modulates PON activity toward paraoxon. Arg 192 (allele B) is associated with higher activity than Gln 192 (allele A). This polymorphism has been proposed as a genetic marker for the risk of coronary artery disease (CAD). However, data on the relationships between biallelic PON1 polymorphisms at codon 192 (A and B alleles) are very controversial. This study was undertaken to evaluate the frequency of high and low activity phenotypes in a control population of healthy individuals taking no medication, and in a group of patients with cardiovascular disease. Restriction polymorphism of PON1 A and B alleles was detected on DNA isolated from EDTA blood by the PCR-RFLP method. Leukocyte DNA was isolated by standard phenol/chloroform extraction and ethanol precipitation protocols. A 99 base pair fragment covering the region containing the mutation was amplified by polymerase chain reaction using PCR Core Kit (Roche, Mannheim, Germany), with primers (MWG – Biotech, Ebersberg Germany) described by Humbert et al, in a Progene Thermal Cycler (Techne, Cambridge, England). PCR products were digested with A1W1, separated by agarose gel (3%) electrophoresis and visualized by use of ethidium bromide. Allele A (glutamine) corresponded to a 99 base pare fragment and allele B (arginine) to a 65 and 34 base pair fragment. Results of the study indicated a difference in biallelic polymorphism between the control group and cardiovascular patients as well as the association of Arg Ž Glu 192 polymorhism with cardiovascular disease.

paraoxonase; CAD

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