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Amino acids in the Tagish Lake MeteoriteHigh-performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated fiom a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P- or D-type asteroids. If the Tagish Lake meteorite was indeed derived fiom these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.
Document ID
20030068413
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Kminek, G.
(Scripps Institution of Oceanography La Jolla, CA, United States)
Botta, O.
(Scripps Institution of Oceanography La Jolla, CA, United States)
Glavin, D. P.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Bada, J. L.
(Scripps Institution of Oceanography La Jolla, CA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Publication Information
Publication: Meteoritics and Planetary Science
Publisher: Meteoritical Society
Volume: 37
Issue: 5
ISSN: 1089-9379
Subject Category
Lunar And Planetary Science And Exploration
Funding Number(s)
CONTRACT_GRANT: NAG5-4546
Distribution Limits
Public
Copyright
Other

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