[Electrophoretic separation of high-molecular protein components of low-density lipoproteins]

Apolipoprotein B (apoB) and 40 different protein standards have been studied at electrophoresis under various conditions of separation. The system was selected that is capable of fractionating well the apoB and its high-molecular weight species formed after the treatment of serum lipoproteins with malondialdehyde. The separation of proteins is based on the usage of complex gels combining in one unit the regions with constant (T = 3 and 10%) or continuously changing (gradient gel with T = 3-6%) concentration of acrylamide. The technique allows to create the optimum conditions for simultaneous separation of both high and low-molecular weight polypeptides. The method was applied to determine the relative molecular mass (Mr) of apoB. When apoB was isolated in strictly controlled environment its Mr has been found to be about 500-540 kilodaltons. The result is in a good accordance with the data on the amino acid sequence of mature apoB.