In vitro oxidized and glycated human low-density lipoprotein particles characterized by capillary zone electrophoresis

A simple capillary zone electrophoresis (CZE) method was used to determine native, in vitro Cu2+ and glucose modified low-density lipoprotein (LDL) particles for four healthy subjects. The LDL electropherograms are highly reproducible with good precisions of effective mobility and peak area. The native LDL capillary electrophoresis (CE) profile shows a major peak with lower mobility and two minor peaks with higher mobilities. For three-hour Cu2+ oxidation, one major peak with mobility close to that of the native major peak, and one minor peak with mobility extending to −47 × 10−5 cm2 V−1 s−1 appear. For eighteen-hour Cu2+ oxidation, one major peak with mobility much higher than that of the native major peak appears. As the reaction time for LDL and Cu2+ increases from 0 to 24 h, effective mobility of the LDL major peak increases, suggesting that LDL particles become more negatively charged and oxidized as the time increases. The in vitro glycated LDL particles are characterized by a major peak and two minor peaks. Mobility of the major peak is close to that of native major peak, but the second minor peak is much more negatively charged with mobility extending to −53 × 10−5 cm2 V−1 s−1. Native, oxidized and glycated LDL particles show distinctive differences in their CZE profiles. Agarose electrophoresis shows that the charge to mass ratios of native, three-hour Cu2+ and glucose modified LDL particles are similar, but that of eighteen-hour Cu2+ oxidized LDL particles is higher.