Physico-chemical properties of copper-oxidized very low density lipoproteins

The aim of our study was to investigate the effect of Cu2+ catalyzed oxidation on VLDL physico-chemical properties and secondary structure of apo B-100. Incubation of very low density lipoproteins with copper ions resulted in a decrease in tryptophan and lysine residues parallel to lipid peroxidation products, conjugated dienes and TBARS. Fluorescence polarization showed an increase in the molecular order at the lipoprotein surface of VLDL, as demonstrated by the increase in Pf values of DPH. The secondary structure of apo B-100 was investigated by infrared spectroscopy. Increased order and structural changes, as observed after oxidative stress on VLDL, could be of relevance in the abnormal interactions between lipoproteins and cell membranes.