Evidence investigation site conditions step

There is further evidence that V(V) may be converted to V02+ in serum, which then binds to the iron transport protein transferrin. This hypothesis is supported by the observation of Hopkins that vanadium, a few hours after injection, becomes associated with transferring. Sabbioni and Marafante176 have also observed a small amount of vanadium bound to serum transferrin. However, in their experiments, and those of Hopkins, no precautions appear to have been taken to protect the vanadium from oxidation during the protein separation steps. Under these conditions, most VOz+ associated with transferrin may be lost from the protein. The possibility that vanadate(V) binds to transferrin has not been investigated. If, in fact, most of the vanadium is bound to transferrin after a few hours, this could explain the failure of red cells to acquire much of the metal. These cells have relatively few receptor sites for the protein. 

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