The Binding of Scandium Ions to Transferrin in vivo and in vitro

Abstract

1 Studies on the binding of scandium to human apotransferrin showed that two Sc3+ were bound specifically at the two iron-binding sites. 2 The binding of each Sc3+ involves the ionisation of two phenolic tyrosyl residues. 3 The scandium · protein complex has similar resistance to denaturants and chemical reagents as the iron complex. 4 The only protein complex observed, when quantities of Sc3+ below the free iron binding capacity of serum were added to whole serum in vitro, was the Sc3+· transferrin complex. 5 The injection of Sc3+, as a 1:2 citrate complex, into rabbits led after 48 h to all the plasma Sc3+ being present as the transferrin complex.