Analysis of apolipoproteins B100 and B48 by sodium dodecyl sulfate polyacrylamide gradient gel electrophoresis

Apolipoproteins B100 and B48 in human and rat plasma were studied by using sodium dodecyl sulfate (SDS) polyacrylamide gradient gel electrophoresis. On SDS gradient gel electrophoresis, human and rat apoprotein B100 co-migrated and had an apparent Mr equal 258,000 +/- 12,000. Human and rat apoprotein B48 had an apparent Mr equal 189,000 +/- 6,000. The molecular weight of human apoprotein B100 determined by sedimentation equilibrium analysis was 270,000 +/- 20,000, which was similar to the value determined by SDS gradient gel electrophoresis. However, on SDS polyacrylamide gel electrophoresis at constant concentration, the relative migration value of human apoprotein B100 was not constant when the concentration of polyacrylamide was changed. These results indicate that SDS gradient gel electrophoresis is more suitable for the analysis of apolipoprotein B's than ordinary SDS polyacrylamide gel electrophoresis.