Epr Evidence for the Oxidation-Induced Formation of Negatively Charged Species on the Low-Density Lipoprotein Surface

Abstract

Oxidation-induced increase of the net negative charge on low-density lipoprotein was studied by electro-phoretic mobility and by electron paramagnetic resonance. The negative-charge increase is associated not only with neutralization of the lysine residues of apoprotein B, but also with the exposition of the excessive negatively charged residues on the lipoprotein surface. The accumulation of the negatively charged residues is believed to be brought about by the conformational change of apoprotein B, triggered by neutralization of lysines and cleavage of peptide bonds. Alternatively, reactive oxygen species could also convert histidine to aspartic acid and proline to glutamic acid.

Key Words:

• EPR
• low-density lipoprotein
• ion binding
• lipoprotein oxidation
• electrophoretic mobility