Metallothionein mimic

Rivero, I.A., Gonzalez, T., Diaz-Garcia, M.E. Synthesis of Metallothionein-mimic decapep-tides with heavy atom signaling Comb. Chem. High Throughput Screen., 2006, 9, 535-544... 

Scheme 23.8 Cu-catalyzed desulfitative catalysis using metallothionein mimics.

Recently it has been shown that Cu(I), as well as its analog Ag(I), can activate metallothionein gene transcription in yeast by binding directly the ACEI trans-activator protein [8 Our experiments with the Ag(I) ion show that it does not appear to mimic the effect of Cu on the accumulation of qrt c-552 mRNA. This could indicate either that the active metalloregulator of the cyt c-552 gene is Cu(II) rather than Cu(I) or that the sensory molecule that responds to Cu is exquisitely specific for Cu (ys. other metals) as the regulator. This level of specificity combined with the extreme sensitivity of the response, < 100 nM total (chelated + free) Cu, suggest that the ( t c-552/Cu-response system could find practical application as a metal ion biosensor. 

There are at least three major types of natural proteins and peptides which are rich in cysteinyl residues metallothioneins, zinc finger proteins, and phytochelatins. The biological role and structural characteristics of metallothioneins are dealt with in Chapter 11 of this book. Zinc finger peptides are possible targets for cadmium(ll) toxicity, while phytochelatins play an important role in the defense mechanisms of plants (Chapter 13). The multicysteine peptides are frequently used to mimic the cadmium(ll) binding ability of all these natural substances. 

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