Affinity isoelectric focusing of human serum apolipoprotein B-containing lipoproteins on agarose gels with cyclodextrins.

In an attempt to subfractionate apolipoprotein B-containing lipoproteins (apoB-Lp), agarose isoelectric focusing (IEF) of apoB-Lp in human sera was carried out in the presence of two kinds of cyclodextrins (CDs), which have different affinities for cholesterol. ApoB-Lp in the agarose gels was detected by immunofixation, followed by protein staining. In the presence of both 11.4 mg/mL alpha-CD and 3.51 mg/mL beta-CD, but not either one alone, IEF separated a maximum of six apoB-Lp bands. Electrophoresis failed to separate the apoB-Lp subfractions under similar conditions with CDs. The patterns of apoB-Lp in IEF with the CDs appeared to differ in some sera. Since the subfractions of apoB-Lp can be separated without ultracentrifugation of serum, the present method serves for the screening of apoB-Lp heterogeneity on native serum lipoproteins.