title: Survivability and reactivity of glycine and alanine in early oceans: effects of meteorite impacts.
abstract: Prebiotic oceans might have contained abundant amino acids, and were subjected to meteorite impacts, especially during the late heavy bombardment. It is so far unknown how meteorite impacts affected amino acids in the early oceans. Impact experiments were performed under the conditions where glycine was synthesized from carbon, ammonia, and water, using aqueous solutions containing (13)C-labeled glycine and alanine. Selected amino acids and amines in samples were analyzed with liquid chromatography-mass spectrometry (LC/MS). In particular, the (13)C-labeled reaction products were analyzed to distinguish between run products and contaminants. The results revealed that both amino acids survived partially in the early ocean through meteorite impacts, that part of glycine changed into alanine, and that large amounts of methylamine and ethylamine were formed. Fast decarboxylation was confirmed to occur during such impact processes. Furthermore, the formation of n-butylamine, detected only in the samples recovered from the solutions with additional nitrogen and carbon sources of ammonia and benzene, suggests that chemical reactions to form new biomolecules can proceed through marine impacts. Methylamine and ethylamine from glycine and alanine increased considerably in the presence of hematite rather than olivine under similar impact conditions. These results also suggest that amino acids present in early oceans can contribute further to impact-induced reactions, implying that impact energy plays a potential role in the prebiotic formation of various biomolecules, although the reactions are complicated and depend upon the chemical environments as well.
authors.affiliation: Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Umeda
authors.affiliation: Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Fukunaga
authors.affiliation: Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan. toshimori-sekine@hiroshima-u.ac.jp.
authors.forename: Toshimori
authors.initials: T
authors.lastname: Sekine
authors.affiliation: Department of Earth and Planetary Materials Science, Tohoku University, Sendai, 980-8578, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Furukawa
authors.affiliation: Department of Earth and Planetary Materials Science, Tohoku University, Sendai, 980-8578, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kakegawa
authors.affiliation: National Institute for Materials Science, Tsukuba, 305-0044, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: National Institute for Materials Science, Tsukuba, 305-0044, Japan.
authors.forename: Hiromoto
authors.initials: H
authors.lastname: Nakazawa
mesh_terms: D000409:Alanine / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D000641:Ammonia / Q000737:chemistry; D001554:Benzene / Q000737:chemistry; D005998:Glycine / Q000737:chemistry*; D007700:Kinetics; D019110:Meteoroids; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry; D011312:Pressure; D012623:Seawater / Q000737:chemistry*; D013696:Temperature
chemical_list: D000588:Amines; D000641:Ammonia; D001554:Benzene; D000409:Alanine; D010100:Oxygen; D005998:Glycine
keywords: Amines; Amino acids; Meteorite impact reactions; Origin of life; Prebiotic chemistry