Very low density lipoprotein subfractions in a subject with broad-β disease (type III hyperlipoproteinemia) and a subject with endogenous lipemia (type IV) chemical composition and electrophoretic mobility

Abstract

1. 1. Three subfractions ( s f 20–60, 60–100, 100–400) of very low density lipoproteins have been isolated from a subject with broad-β disease (Type III hyperlipoproteinemia) and a subject with endogenous (Type IV) lipemia by preparative ultracentrifugation through a saline density gradient. The subfractions and the entire very low density lipoproteins, isolated in a single, separate ultracentrifugation, have been examined by analytical ultracentrifugation, paper and agarose electrophoresis, and chemical analysis. Recovery in the three subfractions as compared with the entire very low density lipoproteins (by both chemical analysis and analytical ultracentrifugation) confirmed the validity of the subfractionation procedure. 2. 2. The subject with broad-β disease exhibited a large quantity of s f > 400 lipoproteins and a very low density lipoprotein distribution with a higher peak S f value than his counterpart with endogenous lipemia. 3. 3. Electrophoresis revealed pre-β mobility for all subtractions in the subject with endogenous lipemia and s f 60–100 and 100–400 subfractions in the subject with broad-β disease; in the latter, β-mobility was confined to the S f 20–60 very low density lipoprotein subclass. 4. 4. In both subjects comparison of chemical composition among subfractions revealed progressive increases in protein, phospholipid, and cholesterol content and a parallel decrease in triglyceride as s f rate decreased. 5. 5. Chemical composition of all very low density lipoprotein subfractions appeared to be normal in the subject with endogenous lipemia. His counterpart with broad-β disease revealed abnormal increases in cholesterol ester and reciprocal decreases in triglyceride in all subfractions.