Characterization of apolipoprotein E-rich high density lipoproteins in familial lecithin:cholesterol acyltransferase deficiency
Mitchell, C.D.; King, W.C.; Applegate, K.R.; Forte, T.; Glomset, J.A.; Norum, K.R.; Gjone, E.
Journal of Lipid Research 21(5): 625-634
1980
ISSN/ISBN: 0022-2275 PMID: 7400692 Accession: 042513191
We have isolated and charachterized a subfraction of high density lipoproteins, rich in apolipoprotein E, from the plasma of patients afflicted with familial lecithin:cholesterol acyltransferase deficiency. Prepared by successive ultracentrifugal flotation, affinity chromatography on heparin-agarose, and affinity chromatography on conconavalin A-agarose, the subfraction contained disc-shaped lipoproteins that measured 14--40 nm in diameter and 4.4--4.5 nm in thickness. The major components were apolipoprotein E, phosphatidylcholine, and unesterified cholesterol, though other apolipoproteins and lipids were present in small amounts. A second subfraction of high density lipoproteins, isolated during the chromatography, contained apolipoproteins A-I and A-II, but no apolipoprotein E. This subfraction included disc-shaped lipoproteins, 13--24 nm in diameter, as well as small round particles, 5.7 nm in diameter. Both subfractions contained similar proportions of total protein relative to lipid, similar amounts of unesterified cholesterol relative to phosphatidylcholine, and a similar distribution of phosphatidylcholine fatty acid.