Isotopic evidence for extraterrestrial non- racemic amino acids in the Murchison meteorite

@article{Engel1997IsotopicEF,
  title={Isotopic evidence for extraterrestrial non- racemic amino acids in the Murchison meteorite},
  author={Michael H. Engel and Stephen A. Macko},
  journal={Nature},
  year={1997},
  volume={389},
  pages={265-268}
}
Many amino acids contain an asymmetric centre, occurring as laevorotatory, L, or dextrorotatory, D, compounds. It is generally assumed that abiotic synthesis of amino acids on the early Earth resulted in racemic mixtures (L- and D-enantiomers in equal abundance). But the origin of life required, owing to conformational constraints, the almost exclusive selection of either L- or D-enantiomers, and the question of why living systems on the Earth consist of L-enantiomers rather than D-enantiomers… Expand
The stereochemistry of amino acids in the Murchison meteorite
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The amplification of L-enantiomers of amino acids from racemates was likely a precondition for the origin of life on Earth. Engel and Nagy1 first reported that seven protein amino acids in theExpand
Possible effects of diagenesis on the stable isotope composition of amino acids in carbonaceous meteorites
  • M. Engel
  • Chemistry, Engineering
  • SPIE Optical Engineering + Applications
  • 2015
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— The varied organic suite extracted from the Murchison meteorite contains several amino acids that are common to the biosphere. Some of these have been found to be non-racemic, but the indigenousExpand
The deuterium enrichment of individual amino acids in carbonaceous meteorites: A case for the presolar distribution of biomolecule precursors
The δD values of over 40 amino acids and two pyridine carboxylic acids of the Murchison and Murray meteorites have been obtained by compound-specific isotopic analyses. For compounds with no knownExpand
Amino Acid Enantiomer Excesses in Meteorites: Origin and Significance
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Assessing the origins of aliphatic amines in the Murchison meteorite from their compound-specific carbon isotopic ratios and enantiomeric composition
The study of meteoritic organic compounds provides a unique window into the chemical inventory of the early Solar System and prebiotic chemistry that may have been important for the origin of life onExpand
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TLDR
The amino acids in the Murchison meteorite are enriched in 13C, indicating an extraterrestrial origin, and Alanine is not racemic, and the 13C enrichment of its D- and L-enantiomers implies that the excess of the L- enantiomer is indigenous rather than terrestrial contamination, suggesting that optically active materials were present in the early Solar System before life began. Expand
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Early determinations of the amino acid distribution in water extracts of the Murchison meteorite revealed unusual amino acids, including isovaline (Ival), α-aminoisobutyric acid (α-Aiba) andExpand
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TLDR
The isotopic composition of hydrogen, nitrogen and carbon in amino acid and monocarboxylic acid extracts from the Murchison meteorite confirms the extraterrestrial origin of both classes of compound, and provides the first evidence suggesting a direct relationship between the massive organo-synthesis occurring in interstellar clouds and the presence of pre-biotic compounds in primitive planetary bodies. Expand
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TLDR
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TLDR
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Carbonaceous chondrites comprise a unique subset of meteorites. Two classes of carbonaceous chondrites, the so-called CI1 and CM2 chondrites, are particularly interesting, in part because of theirExpand
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TLDR
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TLDR
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TLDR
The possibility of sampling bias needs to be tested experimentally before concluding that extraction is complete, and that the constant relative abundances indicate that the relative concentrations of amino acids are homogeneous in the meteorite. Expand
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