Isoform heterogeneity and lipid affinity of human lymph and plasma apolipoprotein A-IV.
We have compared the physical properties and lipid affinity of apolipoprotein A-IV isolated from lymph chylomicrons and from lipoprotein-depleted plasma. Lymph and plasma apolipoprotein A-IV demonstrated distinctly different charge properties as assessed by anion exchange chromatography and isoelectric focusing. These differences were not attributable to disparities of amino acid or sialic acid content. Lymph apolipoprotein A-IV displayed a significantly higher affinity than plasma apolipoprotein A-IV for particles of a phospholipid-triglyceride emulsion. We conclude that the charge properties of human lymph and plasma apolipoprotein A-IV may determine conformational states which alter its ability to bind to the surface of lipid particles.
D001054:Apolipoproteins A / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D002852:Chromatography, Ion Exchange; D002914:Chylomicrons / Q000378:metabolism; D006801:Humans; D007525:Isoelectric Focusing; D007526:Isoelectric Point; D050356:Lipid Metabolism; D008196:Lymph / Q000378:metabolism*; D011487:Protein Conformation
D001054:Apolipoproteins A; D002914:Chylomicrons; C022205:apolipoprotein A-IV