Human placental ferritin receptor

• Published in: Biochimica et biophysica acta Vol. 884; no. 1; p. 31
• Main Authors: Takami, M, Mizumoto, K, Kasuya, I, Kino, K, Sussman, H H, Tsunoo, H
• Format: Journal Article
• Language: English
• Published: Netherlands 29-10-1986
• Subjects: Apoferritins - metabolism; Binding, Competitive; Female; Ferritins - metabolism; Humans; Hydrogen-Ion Concentration; Iron-Binding Proteins; Microvilli - metabolism; Placenta - metabolism; Pregnancy; Radioligand Assay; Receptors, Cell Surface - isolation & purification
• ISSN: 0006-3002
• DOI: 10.1016/0304-4165(86)90223-0

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.