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A search for extraterrestrial amino acids in carbonaceous Antarctic micrometeoritesAntarctic micrometeorites (AMMs) in the 100-400 microns size range are the dominant mass fraction of extraterrestrial material accreted by the Earth today. A high performance liquid chromatography (HPLC) based technique exploited at the limits of sensitivity has been used to search for the extraterrestrial amino acids alpha-aminoisobutyric acid (AIB) and isovaline in AMMs. Five samples, each containing about 30 to 35 grains, were analyzed. All the samples possess a terrestrial amino acid component, indicated by the excess of the L-enantiomers of common protein amino acids. In only one sample (A91) was AIB found to be present at a level significantly above the background blanks. The concentration of AIB (approximately 280 ppm), and the AIB/isovaline ratio (> or = 10), in this sample are both much higher than in CM chondrites. The apparently large variation in the AIB concentrations of the samples suggests that AIB may be concentrated in rare subset of micrometeorites. Because the AIB/isovaline ratio in sample A91 is much larger than in CM chondrites, the synthesis of amino acids in the micrometeorite parent bodies might have involved a different process requiring an HCN-rich environment, such as that found in comets. If the present day characteristics of the meteorite and micrometeorite fluxes can be extrapolated back in time, then the flux of large carbonaceous micrometeorites could have contributed to the inventory of prebiotic molecules on the early Earth.
Document ID
20040172560
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Brinton, K. L.
(Scripps Institution of Oceanography, University of California at San Diego 92093 United States)
Engrand, C.
Glavin, D. P.
Bada, J. L.
Maurette, M.
Date Acquired
August 22, 2013
Publication Date
October 1, 1998
Publication Information
Publication: Origins of life and evolution of the biosphere : the journal of the International Society for the Study of the Origin of Life
Volume: 28
Issue: 4-6
ISSN: 0169-6149
Subject Category
Exobiology
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Exobiology

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