Pizzarello S, Krishnamurthy R V, Epstein S, Cronin J R
Department of Chemistry and Center for Meteorite Studies, Arizona State University, Tempe 85287-1604.
Geochim Cosmochim Acta. 1991;55:905-10. doi: 10.1016/0016-7037(91)90350-e.
Previous isotopic analyses of the total amino acids of the Murchison meteorite showed these compounds to be substantially enriched in 2H, 13C, and 15N relative to terrestrial organic matter. These analyses have been repeated (2H, 13C) with inclusion of an ultrafiltration step to exclude the possibility that a fine particulate contaminant carried the isotopic excesses observed in the previous work. In addition, the meteorite amino acids were chromatographically separated to rule out the possibility that the isotopic enrichment of the meteorite extract could reside in basic compounds other than amino acids. The results indicate that the Murchison amino acids are truly isotopically unusual, that the isotopic excesses reside in at least several different amino acids, and that the isotopic contents of some of these amino acids reach values of about +40% (delta 13C) and +2500% (delta D). If it is assumed that the high deuterium content of the meteorite alpha-amino acids is a result of the synthesis of their molecular precursors by low temperature ion-molecule reactions in an interstellar cloud, their formation by aqueous phase Strecker reactions in the parent body is consistent with their general characteristics and with known parent body processes.
此前对默奇森陨石中总氨基酸的同位素分析表明，相对于地球有机物，这些化合物在2H、13C和15N上显著富集。这些分析（2H、13C）已重复进行，并增加了超滤步骤，以排除在前一项工作中观察到的同位素过量是由细颗粒污染物所致的可能性。此外，对陨石氨基酸进行了色谱分离，以排除陨石提取物的同位素富集可能存在于氨基酸以外的碱性化合物中的可能性。结果表明，默奇森陨石中的氨基酸在同位素方面确实不同寻常，同位素过量存在于至少几种不同的氨基酸中，并且其中一些氨基酸的同位素含量达到约+40%（δ13C）和+2500%（δD）。如果假设陨石α-氨基酸的高氘含量是星际云中低温离子-分子反应合成其分子前体的结果，那么它们在母体中通过水相斯特雷克反应形成与它们的一般特征以及已知的母体过程是一致的。
