| Regional Biophysics Meeting 2005, March 16-20, Zreče, Slovenia | [MembBiophys] |
Microscopic model of slow oxidation of low-density lipoprotein Janko N. Herak* and Dubravka Krilov¤ *Faculty of Pharmacy and Biochemistry and ¤Medical School, University of Zagreb Zagreb, Croatia E-mail: jaherak@pharma.hr Oxidized low-density lipoprotein (oLDL) plays an important role in atherogenesis. Low-density lipoprotein (LDL) contains various antioxidants, the most abundant being alpha-tocopherol. In slow oxidation processes alpha-tocopherol behaves as a pro-oxidant and participates in the tocopherol-mediated peroxidation (TMP). The microscopic probabilistic model of slow TMP of LDL assumes the initiation of oxidation by the transition-metal ions (copper) associated with the lipoprotein. The ions attack interchangeably alpha-tocopherol and lipid hydroperoxide, oscillating between the oxidized and the reduced states. The empirical, macroscopic quantities are related with the microscopic probabilities by a set of five differential equations, containing five or six adjustable parameters. The equations are numerically solved in a finite difference approach. The model decsribes quite well the experimentally observed temporal behavior of five quantities - oxidation markers. Tocopherol and copper ions behave as catalysts. The fitting of the theoretical model to the experimental data resulted in determination of the numerical values for the kinetic parameters. The present model also accounts for the processes in the LDL systems without seeded hydroperoxide. This is probably the first theoretical account demonstrating such a possibility.
Email: jaherak@pharma.hr
Address: Faculty of Pharmacy & Biochemistry, UNiversity of Zagreb, Ante Kovačića 1, 10000 Zagreb, Croatia