宇宙及び惑星極限環境下での有機物質進化とアミノ酸立体化学に関する研究

• Main Author: 高野 淑識
• Format: Article in Journal/Newspaper
• Language: Japanese
• Published: 日本分析化学会 2005
• Subjects: permafrost
• Online Access: http://hdl.handle.net/10131/8370; https://ynu.repo.nii.ac.jp/?action=repository_uri&item_id=4265; https://ynu.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4265&item_no=1&attribute_id=20&file_no=1

Stereo chemical verifications of amino acids regarding organic cosmochemical and geochemical approaches were systematically performed. Representative results are as follows. At first, endo- and exogenous abiotic formations of bio-organic compounds were investigated. Among these, we clarified that the primary irradiation products were not free amino acid analogs, but were amino acid precursors having high molecular weight; both proteinous and non-proteinous amino acids were detected after acid-hydrolysis. Secondary, the emergence of an enantiomeric excess of chiral amino acids in meteorite was experimentally verified. The synthesized complex organics containing amino acid precursors from simple gas mixtures were irradiated with right (R-) or left (L-) continuous ultraviolet circularly polarized light (UV-CPL) obtained from synchrotron radiation (SR). Then, R-CPL preferentially photosynthesized D-alanine, and L-CPL yielded more L-alanine. Statistically significant enantiomeric excesses (%_D-%_L) of +0.44% and -0.65% were obtained by R-CPL and L-CPL, respectively. Thirdly, geological samples in terrestrial extreme environments, such as a semi-permafrost environment, subterranean hydrothermal systems, and deep-sea hydrothermal systems, were analyzed in terms of the concentration of amino acids, the chiral ratio and the enzymatic activities to search for new biospheres. The present findings are therefore strong evidence that those frontiers are previously unknown extreme environment biospheres extending the planetary habitable zone.