Concerning the catalytic amino acids, dileucine yields show a positive feedback on all three catalysts, whereas both histidine enantiomers

are much more effective for diarginine formation than glycine, and none of them contributes to boost the methionine reaction except at low concentrations. The differences above FK228 order can be attributed to several interacting factors such as the complex-formation coefficient (Shoukry, et al. 1997), the polarity, the size, the hydrophobicity, and the nucleophilicity and electrophilicity etc. Fitz, D., Reiner, H., Plankensteiner, K., and Rode, B. M. (2007). Possible origins of biohomochirality. Current Chemical Biology, 1(1): 41–52. Li, F., Fitz, D., Fraser, D. G., and Rode, B. M. (2008). Methionine peptide formation under primordial earth conditions. Journal of Inorganic Biochemistry, 102(5–6): 1212–1217. Rode, B. M. (1999). Peptides and the origin of life. Peptides, 20(6): 773–786. Schwendinger, M. G. and Rode, B. M. (1989). Possible role of copper and sodium chloride in prebiotic formation of peptides. Analytical Sciences, 5(4): 411–414. Shoukry, Thiazovivin manufacturer M. M., Khairy, E. M., and Khalil, R. G. (1997). Binary and ternary complexes involving copper(II), glycyl-DL-leucine and amino acids or amino acids BAY 80-6946 in vitro esters: hydrolysis and equilibrium studies. Transition Metal Chemistry, 22(5):

465–470. E-mail: feng.​li@worc.​ox.​ac.​uk Polymerisation of Amino Acids on Oxide Surfaces I. Lopes Laboratoire de Réactivité de Surface-UMR-7609, Université Pierre et Marie Curie, Paris, France. Amino acids are essential components of living matter and the description of their initial polymerisation to form peptides remains a major problem in the establishment of reasonable origins of life scenarii (Lambert, 2008). It has been proposed

(Bernal, 1950) that the prebiotic polymerisation of amino acids occurred in the adsorbed state on mineral oxide surfaces because this reaction is thermodynamically unfavourable in aqueous phase. This could Tyrosine-protein kinase BLK have occurred at the surface of the primitive earth and/or on interstellar material. Here we present a comparative study of adsorption and thermal activation of different amino acids on different common oxides such as silica and titanium oxide. Several amino acids carrying different side chains, and therefore having a different acid-base speciation, were considered. The adsorption isotherms were established by HPLC, and the adsorbed molecules were characterized by IR spectrometry (Meng et al., 2004) and 13C and 15N solid-state NMR (Stievano et al., 2007). These techniques were also employed, together with thermogravimetry and mass spectrometry to follow the thermal activation of the adsorbed amino acids in the adsorbed state.