Catabolism of globin-haptoglobin in liver cells after intravenous administration of hemoglobin-haptoglobin to rats.

摘要: The intracellular site of uptake and degradation globin-haptoglobin, the protein moiety hemoglobin-haptoglobin, in rat liver cells was investigated vivo. Hemoglobin-haptoglobin, administered intravenously to rats, is cleared from circulation incorporated exclusively into parenchymal through receptor specific for molecule (Kino, K., Tsunoo, H., Higa, Y., Takami, M., Hamaguchi, Nakajima, H. (1980) J. Biol. Chem. 255, 9616-9620). Intrahepatocellular distribution radioactivity determined after intravenous administration (125I-hemoglobin)-haptoglobin or hemoglobin-(125I-haptoglobin) rats. 125I-labeled hemoglobin-haptoglobin first organelles low density (density range, 1.05-1.07 g/ml) recovered Golgi subfractions a substantially intact form. progressively acquired higher density, presumably fusion with primary lysosomes. In resulting high 1.07-1.15 g/ml), which are probably secondary lysosomes, dissociated symmetrically yield two 82,000-dalton subunits by limited proteolysis, further digestion constituent polypeptide chains seemed proceed thereafter during transport process across cells.