Determination of the molecular weight of apoprotein subunits from low density lipoprotein by gel filtration.

Another method has been developed for obtaining a soluble apoprotein from the low density lipoprotein (LDL) of human plasma in the density class 1.019 < d < 1.063. The approximate molecular weight of the apoprotein subunit from this lipoprotein density class was determined by gel filtration on Sephadex G-200 to be about 80,000. Both on gel filtration and analytical ultracentrifugation the soluble apoprotein showed one peak, but on cellulose acetate electrophoresis it showed two bands, which suggests two differently charged components. Because of the nature of the determination, the value of 80,000 probably represents an upper limit to the molecular weight of the LDL subunits.