engleski

Probabilistic kinetic model of slow oxidation of low-density lipoprotein ; hydroperoxide-free initiation

PROBABILISTIC KINETIC MODEL OF SLOW OXIDATION OF LOW-DENSITY LIPOPROTEIN ; HYDROPEROXIDE-FREE INITIATION Dubravka Krilov1 and Janko N. Herak2 1Medical School, Šalata 3b, 2Faculty of Pharmacy and Biochemistry, A. Kovačića 1, University of Zagreb, 10000 Zagreb, Croatia, krilov@mef.hr Theoretical model is presented that explains slow copper-induced oxidation of low-density lipoprotein from human plasma in the systems free of seeded hydroperoxides. The LDL oxidation is assumed to be initiated by traces of the transition-metal ions associated with the lipoprotein. The theory assumes oscillation of the metal ions and a-tocopherol between the oxidized and the reduced states. In this model a-tocopherol acts as a pro-oxidant. The model is based on the probabilistic kinetic theory, modified to take into account different radical generation rates by oxidized and reduced forms of the metal ions. The differential equations describing the initial radical generation rate and the rates of change of concentration of oxygen, hydroperoxide and co-antioxidant in an LDL system are numerically solved in a finite difference approach. It is shown that the initiation and progression of LDL oxidation can take place in any LDL dispersion containing at least a minute amount of the reduced form of the metal ions. Selected values of several adjustable parameters define actual temporal profiles of the quantities defining the oxidation process.

alpha-tocopherol; pro-oxidant; atherosclerosis; LDL; oxidation; peroxidation kinetics; tocopherol-mediated peroxidation

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