Relationships between iron and vanadium metabolism: the association of vanadium with bovine lactoferrin

Bovine milk was incubated simultaneously with 48VO2+ and 59Fe3+ ions. The lactoferrin was separated by ion exchange gel chromatography on CM Sephadex C-50 resin. Sephacryl 200 gel filtration of the lactoferrin-containing fractions, from ion exchange chromatography was carried out to dertermine the proportions of 48V and 59Fe radioactivities associated with macromolecules of the size of lactoferrin. It was found that 48V was incorporated into lactoferrin, the milk protein which contains iron. This suggests that lactoferrin may play a role in the bioavailability of vanadium during lactation, as vanadium is an essential element for the growth of some animal species. More generally, the vanadium binding properties of lactoferrin further support previous findings on the possible biochemical role of Fe-containing non hemoproteins in the metabolism of vanadium.