A simple mixing with carbon monoxide (CO), elemental sulfur (S0), and hydrogen sulfide (HS–) in a warm alkaline solution (pH 9.3 and 35 or 50oC) was found to strongly promote dimerization of amino acids by a research group of Dr. Norio Kitadai (JAMSTEC). It was demonstrated that incubation of 1 mmol L–1 glycine with the three inorganic compound led day- to week-scale increase in the yield of glycylglycine up to 18%. Dimerization of 0.01 mmol L–1 glycine was also observed (0.4 % yield). 0.01 mM is the lowest concentration of amino acid oligomerized experimentally in the prebiotic context. The demonstrated favorable condition for amino acid dimerization is likely to have occurred on the primordial Earth and Mars. This possibility supports an abiotic appearance of peptides and thereby facilitated protometabolism on the CO world environments.
The research results were published in Geochemica et Cosmochimica Acta on 3 April 2023.