Transferrin (E7F4T) Rabbit mAb #35293

Transferrin is the major ferric iron transport protein, which binds ferric (Fe3+) ions in association with the binding of an anion, usually bicarbonate (1). The iron binding affinity of transferrin is pH dependent. In a neutral pH environment, transferrin (apotransferrin) binds iron with high affinity to form iron-bound transferrin (holotransferrin). In an acidic pH environment, the affinity of iron bound to transferrin decreases, dissociating iron from holotransferrin and releasing it into the environment (2). The importance of holotransferrin is to sequester Fe3+ ions in a relatively nonreactive and inert state to ensure normal free iron homeostasis in the body (3). Transferrin has been shown to contribute to iron-related oxidative damage (4), DNA synthesis (5), cell growth (6), and differentiation (7). Holotransferrin delivers iron to cells by binding to transferrin receptor (TFR1 or TFR2). Neutral pH at the cell surface promotes binding of holotransferrin to TFR1/TFR2. The receptor-ligand complex enters the cell through receptor-mediated endocytosis and is internalized into an endosome. Relatively lower endosomal pH results in the release of iron. The receptor-ligand complex is recycled to the cell surface, where apotransferrin dissociates from TFR1/TFR2 (8).