THE ROLE OF LIPID HYDROPEROXIDES IN THE MYOGLOBIN-DEPENDENT OXIDATIONOF LDL

It has previously been reported that Mb in both the iron-ore ferryl an d the ferric oxidation states can promote lipid peroxidation and lead to oxidative modification of low-density lipoprotein. The mechanism of these oxidation reactions is unclear and could involve either lipid h ydroperoxide-dependent or independent reactions. In order to ascertain which of the afore-mentioned mechanisms predominates, the effects of exogenous lipid hydroperoxides on the ability of Mb, in its various ox idation states, to oxidize low-density lipoprotein has been investigat ed. The results suggest that oxidation proceeds through a one-electron redox cycle between met and ferryl myoglobin and that the reactions o f both redox forms are at least partially dependent on lipid hydropero xides within the LDL particle. (C) 1994 Academic Press, Inc.