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

It has previously been reported that Mb in both the iron-ore ferryl and 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 hydroperoxide-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 oxidation states, to oxidize low-density lipoprotein has been investigated. The results suggest that oxidation proceeds through a one-electron redox cycle between met and ferryl myoglobin and that the reactions of both redox forms are at least partially dependent on lipid hydroperoxides within the LDL particle. (C) 1994 Academic Press, Inc.