IRON AND FREE RADICAL OXIDATIONS IN CELL MEMBRANES

摘要: Brain tissue being rich in polyunsaturated fatty acids, is very susceptible to lipid peroxidation. Iron well known be an important initiator of free radical oxidations. We propose that the principal route iron -mediated peroxidations via iron-oxygen complexes rather than reaction with hydrogen peroxide, Fenton reaction. To test this hypothesis, we enriched leukemia cells (K-562 and L1210 cells) docosahexaenoic acid (DHA) as a model for brain tissue, increasing amount DHA from approximately 3 mole % 32 %. These were then subjected ferrous dioxygen initiate peroxidation presence or absence peroxide. Lipid-derived radicals detected using EPR spin trapping α-(4-pyridyl-1-oxide)-N-t-butylnitrone (POBN). As expected, lipid-derived formation increases cellular unsaturation. Experiments Desferal demonstrate required these cells. Addition DHA-enriched resulted significant amounts formation; increased iron. However, exposure peroxide before addition did not increase formation, but actually decreased adduct formation. data suggest are primary initiation biological This proposes mechanism explain how catalytic can so destructive.