Siderophores vanadium complexes

Vanadium, as V0S04, has been found to interfere with siderophore-mediated iron transport in bacteria and plants. This seems to imply that vanadium can be transported by siderophores, and a number of studies focussing on applications of hydroxamate V-complexes in biology have been initiated. 

Iron is transported in forms in which it is tightly complexed to small chelators called siderophores (microorganisms) or to proteins called transferrins (animals) or to citrate or mugeneic acid (plants). The problem of how the iron is released in a controlled fashion is largely unresolved. The process of mineral formation, called biomineralization, is a subject of active investigation. Vanadium and molybdenum are transported as stable anions. Zinc and copper appear to be transported loosely associated with peptides or proteins (plants) and possibly mugeneic acid in plants. Much remains to be learned about the biological transport of nonferrous metal ions. 

Three other metals, namely, copper, vanadium, and molybdenium, possess appreciable affinities for siderophores. It is possible that siderophores or siderophore-like molecules are involved in the microbial transport of these metals. Copper(II) forms stable complexes with hydroxamate siderophores (for instance, schizokinen, desferriox-amine B. and desfeirithiocin) and catechol siderophores (for instance, enterobactin). However, copper(II), unlike iron(III), also possesses a high affinity for amino acids and small peptides, and this property renders it unlikely that copper uptake is dependent on siderophore-medi-ated transport. 

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