Ionic and molecular mimicry and the transport of metals

Abstract

Toxic, nonessential metals, such as mercury, cadmium, and lead, have no known nutritive value. Accordingly, in most animal species, there appear to be no dedicated mechanisms for the uptake of these metals into target cells. Yet, many studies have proven that these toxic metals do indeed gain entry into various target cells in affected tissues and organs [1-5]. In recent years, the concepts of molecular mimicry and ionic mimicry have been postulated as mechanisms by which certain toxic metal species can gain entry into target cells. Molecular mimicry has been defined previously as “the phenomenon whereby the bonding of metal ions to nucleophilic groups on certain biomolecules results in the formation of organo-metal complexes that can behave or serve as structural and/or functional homologs of other endogenous biomolecules or the molecule to which the metal ion has bonded” (Figure 10.1) [1-4]. Molecular mimicry appears to play a significant role in the entry of certain metals into cells that become intoxicated by one or more of these metals.