Difference between OxLDL and MM-LDL. LDL is thought to be modified in a stepwise manner during the generation of OxLDL. In the initial phase of modification, the lipid components (sky blue circle) react with oxidation reagents, resulting in radical chain reactions that produce many types of lipid oxidation products (red, brown, yellow, or dark blue circle). Then, the lipid oxidation products react with the apoB protein (blue line) to generate adducts and cross-links. Radicals can attack the apoB protein directly, resulting in oxidative changes of amino acid side chains and the cleavage of peptide bonds (orange-grey line). MM-LDL may contain lipid oxidation products without extensive protein modification, because it binds to LDL receptor rather than scavenger receptors. As modification on the apoB protein proceeds, its mobility in the agarose gel electrophoresis changes greatly, and it loses the affinity to LDL receptor, and, in turn, it becomes a ligand of scavenger receptors.
