We propose that K+ complies with all the above-listed requirements, which is unique in contrast to other mono- and divalent metallic ions (Fig. 3). Further peptide evolution at later stages could have occurred due to the presence of other abundant cations, e.g., Na+, Mg2+ and Ca2+, which may have resulted from their lower diffusion and higher hydration energy. The elongation and functionalization of the peptides might also have been driven by other inorganic cations or clays or minerals (Ferris et al. 1996; Hill and Orgel 1999; Rode et al. 1999; Rees and

Howard 2003) because they form more stable complexes with biomolecules. We assume that our findings could be useful not only for discussions of the origin of life but also for more sophisticated research on the role of the physical-chemical properties of inorganic ions, biomolecules and nanoparticles

in molecular physiology. The EX 527 order data on the difference in K+ versus Na+ coordination- and diffusion-controlled condensation of amino acids may be of particular interest in understanding ion-exchange regulation by the membrane Na+/K+-ATPase pump. Acknowledgments We are grateful to Prof. Yuri V. Trushin and Prof. Vladimir G. Dubrovskii for helpful discussions of the physics of diffusion, Dr. Viktor G. Zgoda for his discussions of mass spectrometry and PhD student Ivan N. Terterov for his technical assistance. This work was performed PD0325901 solubility dmso under a grant from the Presidium of the Russian Academy of Sciences. Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. References Aronson PS, Boron WF, Boulpaep EL (2009) Transport of solutes and water. In: Boron WF, Boulpaep EL (eds) Medical physiology, 2nd edn.

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