Polymerization-induced enhancement of binding and binding-induced polymerization

We obtained the binding free energy of the complex [Co(C2O4)3]3− to the peptide H–Lys–Gly–(Lys–Gly)9–Lys–NH2, and to the monomers (aminoacids) forming the peptide, using the electron transfer reaction between [Ru(NH3)5pz]2+ and [Co(C2O4)3]3− as the probe. The polymerization of the monomers increases the negative free energy of binding and changes its character, non-cooperative for the monomers and anti-cooperative for the peptide. This increase in the negative free energy represents a driving force for the polymerization process that produces the peptide from the aminoacids (monomers) in such a way that the polymerization in the presence of the cobalt complex is more favourable, from a thermodynamic point of view, in 16.5 kJ/mol.