Abiotic synthesis of amino acids and imidazole by proton irradiation of simulated primitive earth atmospheres

Abstract

Abstract. Proton irradiation of simulated primitive earth atmosphere was performed, and amino acids and imidazole were analyzed. A mixture of carbon monoxide and nitrogen over water was irradiated by high energy protons (3 Me¥, 0.6 gA) generated by a Van de Graaff accelerator for 2-5 h. Various kinds of proteinous and non-proteinous amino acids were detected in the irradiation products. Imidazole present in the irradiation products was also detected by high-performance liquid chromatography and mass spectrometry. The present results suggest that compounds of biological importance such as amino acids could be synthesized from primitive earth atmosphere by radiation of cosmic rays and/or solar flare particles.

Role of Clay Minerals in Chemical Evolution and the Origins of Life

“…Further, bio-organic molecules are difficult to obtain under the conditions used by Miller (1953) [14]. In an attempt to make for favorable conditions, Kobayashi et al (1990) used proton irradiation to produce a reducing atmosphere from an oxidizing one [17]. Nevertheless, the role of clay minerals in the formation of bio-molecules remains uncertain.…”

“…Adenine was formed, however, when a mixture of HCN and montmorillonite was added to the reaction vessel, and exposed to lightning [15]. Similarly, uracil could be synthesized from CO, N2 and H2O by proton irradiation [17]. …”

The Propitious Role of Solar Energetic Particles in the Origin of Life

“…Lastly, the G-values associated with amino acid synthesis through irradiation by energetic protons (∼ 0.01) are amongst the highest documented for prebiotic pathways (Kobayashi et al 1990). This is an important point since it indicates that, despite the lower energy flux of SEPs, the resultant yield of organic molecules can be higher when compared to a few other energy sources.…”

“…• Uracil, guanine, adenine and cytosine (Kobayashi et al 1990;Miyakawa et al 2002b), which represent four of the five nucleobases of RNA and DNA. The absence of thymine (DNA only) might favor the emergence of RNA prior to DNA, in accordance with the RNA world hypothesis (Joyce 2002;Orgel 2004).…”

“…Using the G-values provided in Kobayashi et al (1990) and Miyakawa et al (2002b), we obtain the following phenomenological relatioṅ…”