Studies on the protein composition of human serum very low density lipoproteins: demonstration of the beta 2-glycoprotein-I.
Human serum VLDL isolated by polyanion precipitation and ultracentrifugation have been delipidated with ethanal/diethyl ether. By electrophoresis in 10% polyacrylamide gels containing 8M urea, we found a protein which comigrated with apolipoprotein E. This protein was purified by column chromatography and turned out to be identical with beta 2-glycoprotein-I, the serum factor which is necessary for the precipitation of triglyceride-rich lipoproteins with sodium decyl sulfate or sodium dodecyl sulfate. Upon analytical isoelectric focusing, beta 2-glycoprotein-I gave four major bands in the pH region 5.7--6.6. All four bands gave an immunochemical reaction of identity with a monospecific antiserum. From its unique amino acid composition we conclude that beta 2-glycoprotein-I is distinct from all apolipoproteins described previously in the literature.
D000596:Amino Acids / Q000032:analysis; D001053:Apolipoproteins / Q000097:blood; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000097:blood; D006801:Humans; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007525:Isoelectric Focusing; D008079:Lipoproteins, VLDL / Q000097:blood
D000596:Amino Acids; D001053:Apolipoproteins; D006023:Glycoproteins; D008079:Lipoproteins, VLDL