title: Human placental coated vesicles contain receptor-bound transferrin.
abstract: Human placental coated vesicles have been purified by a method involving sucrose-density-gradient centrifugation and treatment with wheat-germ agglutinin. These preparations were free of contamination by placental microvillus fragments. Crossed immunoelectrophoresis demonstrated that the coated vesicles contained a single serum protein, which was identified as transferrin. This transferrin was only observed after the vesicles were treated with a non-ionic detergent, and its behaviour during crossed hydrophobic-interaction immunoelectrophoresis suggested that a large proportion of it was receptor-bound. No other serum proteins, including immunoglobulin G, could be detected in these preparations. Receptor-bound transferrin was the only antigen common to placental coated vesicles and microvilli, implying that other plasma-membrane proteins are excluded from the region of membrane involved in coated-vesicle formation.
mesh_terms: D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005293:Ferritins / Q000032:analysis; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007074:Immunoglobulin G / Q000032:analysis; D066298:In Vitro Techniques; D008871:Microvilli / Q000032:analysis; D010920:Placenta / Q000032:analysis* / Q000648:ultrastructure; D011247:Pregnancy; D011956:Receptors, Cell Surface / Q000032:analysis*; D011990:Receptors, Transferrin; D014168:Transferrin / Q000032:analysis
chemical_list: D007074:Immunoglobulin G; D011956:Receptors, Cell Surface; D011990:Receptors, Transferrin; D014168:Transferrin; D005293:Ferritins