Chromium(III) and Transferrin
Transferrins comprise a class of proteins with molecular weights of approximately 80,000 that reversibly bind two equivalents of metal ions. The proteins selectively bind ferric ions in a biological environment because the metal-binding sites are adapted to bind ions with large charge-to-size ratios. Transferrin is a blood serum protein, a β-globulin, although other forms of the protein are found in milk (lactoferrin) and avian egg white (conalbumin or ovotransferrin). Transferrin is the major iron transport protein in the bloodstream, while lactoferrin and conalbumin are believed to have antibacterial roles by depriving bacteria of iron. Because of its similarity in size and charge to ferric ion, Cr3+ is transported and stored in the bloodstream by transferrin.
Transferrins are a class of proteins of approximately 80 kDa (kilodaltons) that reversibly bind two equivalents of metal ions (Brock 1985). The...