title: Beta-lipoprotein cholesterol quantitation with polycations.
abstract: We compared direct determination of beta-lipoprotein cholesterol after selective extraction of very-low-density and high-density lipoproteins from serum with poly(ethyleneimine) and a cation-exchange resin with the classical quantitation after lipoprotein fractionation with the ultracentrifuge. At beta-lipoprotein cholesterol concentrations between 1.50 and 5.00 g/liter the correlation is linear (r = 0.95). The precision for the extraction procedure is as good (CV 2.4-2.8%) as for the quantitation by ultracentrifugation (CV 3.2-6.0%). From solutions of isolated lipoproteins, very-low-density lipoproteins are 93% extracted and high-density lipoproteins 60%, but low-density-lipoproteins only 5%. The molecular mechanism of the extraction is supposed to be due to both hydrophobic interaction of long-chain fatty acid residues and ionic interaction of phospholipids located at the surface of very low-density and high-density lipoproteins and the lipophilic polycation.
mesh_terms: D002784:Cholesterol / Q000097:blood*; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood; D007475:Ion Exchange Resins; D008074:Lipoproteins / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood*; D011094:Polyethyleneimine; D011095:Polyethylenes; D012710:Serum Albumin, Bovine; D014280:Triglycerides / Q000097:blood; D014461:Ultracentrifugation
chemical_list: D007475:Ion Exchange Resins; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D011095:Polyethylenes; D014280:Triglycerides; D012710:Serum Albumin, Bovine; D011094:Polyethyleneimine; D002784:Cholesterol