title: Human placental ferritin receptor.
abstract: Brush-border membranes from human placenta were prepared and their purity was clarified by biochemical and morphological methods. Ferritin binding to these prepared membranes was examined using horse spleen 125I-apoferritin, and was found to be completed within 10 min at 37 degrees C and pH 7.5. The amount of ferritin bound to the membranes was found to be proportional to the amount of membrane added and saturable for a given amount of the membrane in the presence of excess ligand. The membranes exhibited specific ferritin binding with a Ka of 2.3 X 10(7) M-1 at pH 7.5. A competitive binding assay indicated that horse spleen 125I-apoferritin binding was inhibited by a 10-fold molar excess of horse spleen ferric ferritin and a 500-fold molar excess of human transferrin. These results suggest that human placental brush-border membranes have specific receptors for horse spleen apoferritin molecules.
mesh_terms: D001052:Apoferritins / Q000378:metabolism; D001667:Binding, Competitive; D005260:Female; D005293:Ferritins / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D033862:Iron-Binding Proteins; D008871:Microvilli / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000302:isolation & purification*
chemical_list: D033862:Iron-Binding Proteins; D011956:Receptors, Cell Surface; C027293:ferritin receptor; D005293:Ferritins; D001052:Apoferritins