The binding and transport of alternative metals by transferrin.

BACKGROUND

The iron transport protein of the blood plasma, transferrin, is maintained only with about 30% of its capacity to bind Fe(3+) ions; this leaves the protein the potential ability to transport other metal ions from the bloodstream to the tissues.

SCOPE OF REVIEW

This review examines the potential role of transferrin to bind and transport alternative metal ions with possible beneficial and deleterious effects.

MAJOR CONCLUSIONS

Transferrin has been postulated to play a significant role in transporting Ti(4+), VO(2+) (V(4+)), Cr(3+), Ru(3+), and Bi(3+), all metal ions of potential therapeutic significance. Transferrin may possess a physiological role in the transport of manganese, as the trivalent ion. However, the protein may also play a role in carrying potentially toxic Al(3+) and actinide ions, including Pu(4+), to the tissues. Attempts to use transferrin in the selective removal of low concentrations of specific metal ions from aqueous mixed ions waste streams using a procedure called metalloprotein affinity metal chromatography are discussed.

GENERAL SIGNIFICANCE

The binding of alternative metals to transferrins may have therapeutic and toxicological significance. This article is part of a Special Issue entitled Transferrins: Molecular Mechanisms of Iron Transport and Disorders.