title: [Dissociation of human serum low density lipoproteins in several immunologically distinct subunits. Isolation and characterization of a B-III subunit].
abstract: Low density lipoproteins (d = 1.030-1.055) were partially delipidated with ethyl-ether (LDLe). These LDLe exhibit a spontaneous dissociation several days after delipidation. Four different immunoprecipitation complexes (B-I to B-IV) are observed when using two dimensional immunoelectrophoresis against anti LDLe immunserum. The various subunits of LDLe have different behaviour upon electrophoresis. On disc gel electrophoresis containing urea three bands can be seen; all are phospholipoproteins. The apolipoprotein moiety of LDL and LDLe have the same apparent molecular weight around 550 000. With time several subunits appear in LDLe, the majority of them have a molecular weight around 370 000, 260 000 and 125 000. One of the components from dissociated LDLe containing the immunodeterminant B-III, has been separated by chromatography on heparin-agarose. This LDLe-B-III has the same phospholipid/protein ratio as total LDLe and a protein moiety with an apparent molecular weight of 110 000. This part of apolipoprotein B has no affinity for heparin. Immunocompetition studies by the ELISA technique indicated that sialic acid, one of terminal residues of LDL glycoprotein, is involved in the immunological recognition of LDL and of its derivatives by anti LDL and anti LDLe antisera.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000936:Antigen-Antibody Complex; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis; D006601:Hexoses / Q000032:analysis; D006801:Humans; D007106:Immune Sera; D007122:Immunoelectrophoresis; D008077:Lipoproteins, LDL / Q000097:blood*; D046911:Macromolecular Substances; D008970:Molecular Weight; D010743:Phospholipids / Q000032:analysis; D012794:Sialic Acids / Q000032:analysis
chemical_list: D000596:Amino Acids; D000936:Antigen-Antibody Complex; D000939:Epitopes; D006601:Hexoses; D007106:Immune Sera; D008077:Lipoproteins, LDL; D046911:Macromolecular Substances; D010743:Phospholipids; D012794:Sialic Acids
vernacular_title: Dissociation of human serum low density lipoproteins in several immunologically distinct subunits. Isolation and characterization of a B-III subunit.