4] Simultaneous quantification of apolipoproteins B-100, B-48, and E separated by SDS-PAGE

Abstract

Publisher Summary The two species of apolipoprotein (apo) B in humans, apoB-100, and apoB-48, define the hepatogenous and intestinal contributions to the secretion of triglyceride-rich lipoproteins (TRL) into the blood. A number of methods have been proposed to quantify apoB-100 and apoB-48. Several procedures based on separation by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) have given inconsistent results. With electrophoresis in 3.3% polyacrylamide tube gels, followed by Coomassie blue staining, Poapst et al. reported a lower chromogenicity for apoB-48 than for apoB-100, as well as a nonlinear response, between the intensity of dye uptake and apolipoprotein mass. This method has been used to quantify apolipoproteins in human triglyceride-rich lipoproteins (TRL) and has yielded apoB-100 and apoB-48 levels that are considerably higher than those reported, by others, using electrophoresis in slab gels. Zilversmit and Shea, using slab gels, found equal chromogenicities for rat apoB-48 and rat and human apoB-100 and a linear relationship between dye uptake and apolipoprotein mass. These observations are consistent with the findings here and those of others who have carried out the electrophoresis of apoB and other proteins in slab gels and they support the conclusion that apoB data obtained by tube gel electrophoresis, in which only a rim of dye penetrates into the gel, should be viewed with caution. A major advantage to the SDS-polyacrylamide slab gel electrophoretic method that has been developed is the ability to quantify apoB-100 and apoB-48 together with apoE in various lipoprotein fractions in humans and other species.