Synthesis of Metallothionein-Mimic Decapeptides with Heavy Atom Signaling Properties

The automated parallel solid-phase synthesis of a 17-member library of metallothionein-mimic decapeptides carrying a Lariat ether group is described. The peptides were synthesized in good yield and the identity and quality of each product were performed by mass spectrometry and IR. Subsequently, in the presence of europium(III) ions as fluorescent reporter, each compound was screened, both attached to the resin and cleaved off, for their sensing behavior towards metal ions (Cd2+, Hg2+, Cu2+, Mg2+ and Ca2+) using fluorimetric techniques. Several of these Cys-enriched synthetic peptides showed surprisingly low detection limits for Cd2+ and Hg2+. The analytical potential of these metallothioneinmimic decapeptides as metal ion recognition materials for sensor development is outlined. Finally, the sensing response mechanism, based on an energy transfer process and a metal ion allosteric interaction, is proposed.