Lipoprotein affinity of human apolipoprotein A-IV during cholesterol esterification.
We have studied the lipoprotein distribution of human apo A-IV during cholesterol esterification by the action of endogenous lecithin-cholesterol acyltransferase. Using immunologic and radiotracer techniques at 4 degrees C, apo A-IV was found in two discrete monomeric and dimeric populations, unassociated with plasma lipoproteins. With incubation at 37 degrees C, apo A-IV initially associated with the high density lipoprotein-3 fraction, but thereafter dissociated from its surface, and reappeared as unbound protein and in association with a complex in the low density lipoprotein size range. Inclusion of LCAT inhibitors in the incubations abolished these changes. We conclude that the changes in lipoprotein distribution of human apo A-IV closely parallel the formation and exchange of plasma cholesteryl esters.
D001054:Apolipoproteins A / Q000378:metabolism*; D002788:Cholesterol Esters / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008075:Lipoproteins, HDL / Q000378:metabolism*; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D001054:Apolipoproteins A; D002788:Cholesterol Esters; D008075:Lipoproteins, HDL; C022205:apolipoprotein A-IV; D007862:Phosphatidylcholine-Sterol O-Acyltransferase