MDA-rich LDLのHeterogeneity

To clarify the heterogeneity of malondialdehyde rich low density lipoproteins (MDA-LDL), LDL from normal plasma (n-LDL) were treated with Malonaldehyde bis (dimethyl acetal) (MDA-LDLM) and CuCl2 (MDA-LDLCu). The elution of n-LDL, uremic LDL (MDA-LDLHD) and MDA-LDL showed that the peak of MDA rich fractions (MRF) was eluted at higher ionic strength than that of MDA poor fractions (MPF) on a gradient ion-exchange chromatography. MDA-LDL, especially MDA-LDLCu, showed an electrophoretic mobility with more negative charge compared to that of n-LDL. In the MRF of n-LDL, MDA-LDLHD and MDA-LDLM, there was the appearance of peptides having a higher molecular weight, besides apo B-100, by SDS-PAGE. On the other hand, in the MDA-LDLCu, a number of peptides having a lower molecular weight were recognized. After all, because MDA-LDLM resembles MDA-LDLHD closely, MDA-LDLM is thought to be a model of oxidatively modified LDL which presents in blood.