Apoprotein B of lipoprotein(a) of human plasma

Lipoprotein(a) was purified by agarose-gel chromatography from human plasma from which lipoproteins of Sf greater than 0 had been removed either by sequential or by density-gradient ultracentrifugation. After delipidation, the apoprotein B of this lipoprotein was analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. It could not be distinguished from the apoprotein B of low-density lipoproteins (rho 1.019-1.063 g/ml). A significant increase in the concentration of apoprotein B in plasma from which the Sf greater than 0 lipoproteins had been removed was observed in six subjects 4 h after a fatty meal.