流星型アミノ酸のエナティオメリック過量
1Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA.
まとめ
隕石のアミノ酸の分析は,アルファメチルアミノ酸のL-エナチオメールの過剰を明らかにし,数十億年前の有機進化に対する生命以前の非対称的な影響を示唆しています.
科学分野:
- 天体生物学 アストロバイオロジー
- オーガニック・ジオケミストリー オーガニック・ジオケミストリー
- 宇宙化学 (コスモケミストリー)
背景:
- 隕石には,アミノ酸を含む有機分子が含まれており,プレバイオティック化学のヒントを提供します.
- マーチソン隕石は炭酸性コンドライトで,初期の太陽系物質のサンプルを提供している.
研究 の 目的:
- マーチソン隕石の特定のアミノ酸のエナティオメール組成を調べるために.
- 地球外のアミノ酸が生命の起源以前にキラリティの兆候を示すかどうかを決定する.
主な方法:
- 立体同位体分析には,ガス染色体-質量スペクトロメトリー (GC-MS) が使用されました.
- 分析は,2-アミノ-2,3-ジメチルペンタノ酸,イソバリン,アルファ-メチルノルヴァリンのステレオイソマーに焦点を当てた.
主要な成果:
- L-エナチオメールの過剰は,2-アミノ-2,3-ジメチルペンタノ酸の立体同位体 (7.0%と9.1%) で観察されました.
- 同様のL-エナチオメールの過剰は,イソバリンとアルファメチルノルヴァリンで発見されました.
- アルファ水素同類 (アルファ-アミノ-n-バテリック酸,ノルヴァリン) はラセミックでした.
結論:
- 隕石のアルファメチルアミノ酸の観察されたエナティオメリック過剰は,地球外でのキラリティの源を示唆しています.
- これらの発見は,地球上の生命より前の有機化学の進化に対する非対称的な影響を示している.
- この結果は,初期の太陽系におけるキラル選択過程の証拠を提供している.
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