Metal – Metal Interactions in Biological System: A Competitive Approach. Review

The increased availability of metals in biological environments, due to human intervention in the last century, raised concerns on the effects that metals might have on living organisms. Consequently, the toxicology of metals and bioinorganic chemistry has emerged as very active in this field of metals research. Different chemical forms can influence metal toxicokinetics and toxicodynamics and should be considered to improve human health risk assessment. Factors that influence metal speciation include: carrier-mediated processes for specific metal species; valence state; particle size; the nature of metal binding ligands; whether the metal is an organic versus inorganic species and biotransformation of metal species. The recent studies of the co-ordination chemistry of metal ions in biological systems (mostly X-ray crystallographic data) show the potential grouping metal ions according to their binding preferences (i.e. whether they seek out 0-, N- or S-containing ligands), on the other hand, the scientific results have shown us for the possibility of metal-metal interaction in biological systems despite their level of concentration. This review provides a compilation of research done on metal - metal interaction in biological system.