Enantiomeric Excesses in Meteoritic Amino Acids

  title={Enantiomeric Excesses in Meteoritic Amino Acids},
  author={John R. Cronin and Sandra Pizzarello},
  pages={951 - 955}
Gas chromatographic-mass spectral analyses of the four stereoisomers of 2-amino-2,3-dimethylpentanoic acid (DL-α-methylisoleucine and DL-α-methylalloisoleucine) obtained from the Murchison meteorite show that the L enantiomer occurs in excess (7.0 and 9.1%, respectively) in both of the enantiomeric pairs. Similar results were obtained for two other α-methyl amino acids, isovaline and α-methylnorvaline, although the α hydrogen analogs of these amino acids, α-amino-n-butyric acid and norvaline… Expand
Amino Acid Enantiomer Excesses in Meteorites: Origin and Significance
Abstract The presence of small l -excesses in both of the two enantiomeric pairs of 2-amino-2,3-dimethylpentanoic acid, in 2-amino-2-methylbutanoic acid (Isovaline), and in 2-amino-2-methylpentanoicExpand
Non-racemic amino acids in the Murray and Murchison meteorites.
The alpha-methyl-alpha-amino alkanoic acids could have been significant in the origin of terrestrial homochirality given their resistance to racemization and the possibility for amplification of their enantiomeric excesses suggested by the strong tendency of their polymers to form chiral secondary structure. Expand
Enrichment of the amino acid l-isovaline by aqueous alteration on CI and CM meteorite parent bodies
The large asymmetry in isovaline and other α-dialkyl amino acids found in altered CI and CM meteorites suggests that amino acids delivered by asteroids, comets, and their fragments would have biased the Earth's prebiotic organic inventory with left-handed molecules before the origin of life. Expand
Molecular and chiral analyses of some protein amino acid derivatives in the Murchison and Murray meteorites
— 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
Partial transfer of enantioselective chiralities from α-methylated amino acids, known to be of meteoritic origin, into normal amino acids
Abstract There is overwhelming evidence that meteorites bring α-methylated amino acids to earth with some l (S) enantiomeric excess. How does that get transferred into normal biological molecules? InExpand
The carbon isotopic distribution of Murchison amino acids
Abstract The δ 13 C values of thirty-four individual amino acids and two pyridine carboxylic acids have been obtained fromthe Murchison meteorite. They were found to range from +4.9 to +52.8‰, withExpand
Isotopic evidence for extraterrestrial non- racemic amino acids in the Murchison meteorite
It is shown that individual amino-acid enantiomers from Murchison are enriched in 15N relative to their terrestrial counterparts, so confirming an extraterrestrial source for an L-enantiomer excess in the Solar System that may predate the origin of life on the Earth. Expand
Nonracemic isovaline in the Murchison meteorite : Chiral distribution and mineral association
Abstract The enantiomeric and carbon-isotopic composition of the amino acid isovaline have been analyzed in several samples of the Murchison meteorite and one sample of the Murray meteorite. lExpand
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
Unusual Nonterrestrial L-proteinogenic Amino Acid excesses in the Tagish Lake Meteorite
The distribution and isotopic and enantiomeric compositions of amino acids found in three distinct fragments of the Tagish Lake C2-type carbonaceous chondrite were investigated via liquidExpand


Distribution and enantiomeric composition of amino acids in the Murchison meteorite
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
Amino acids of the Murchison meteorite. III. Seven carbon acyclic primary alpha-amino alkanoic acids.
Fifty-five amino acids have now been positively identified in the Murchison meteorite, 36 of which are unknown in terrestrial materials, and this unique suite of amino acids is characterized by the occurrence of all structural isomers within the two major classes of amino acid represented. Expand
Mass spectral analysis of C 3 and C 4 aliphatic amino acid derivatives.
Using the above criteria and consideration of the effects of methyl and ethyl substituents it appears possible to identify most of the C 3 and C 4 aliphatic amino acids by the mass spectra of their N -TFA-alkyl ester derivatives. Expand
Amino acids of the Murchison meteorite: II. Five carbon acyclic primary beta-, gamma-, and delta-amino alkanoic acids.
Thirty-six amino acids have now been positively identified in the Murchison meteorite, 17 of which are apparently unique to carbonaceous chondrites, consistent with a synthetic process involving random combination of single-carbon precursors. Expand
Isoleucine stereoisomers on the Earth
The amino acid L-isoleucine (L-Ile) undergoes epimerization at the α-carbon producing D-allo-isoleucine (D-aIle), an amino acid not generally found in living organisms. In fossils and oceanicExpand
Characteristics and formation of amino acids and hydroxy acids of the Murchison meteorite.
The marked structural correspondence between the alpha-amino acids and alpha-hydroxy acids and the high deuterium/hydrogen ratio argue persuasively for their formation by aqueous phase Strecker reactions in the meteorite parent body from presolar. Expand
Unusual stable isotope ratios in amino acid and carboxylic acid extracts from the Murchison meteorite
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
Nonprotein amino acids in the murchison meteorite.
Tentative evidence is presented for the presence of N-methylalanine, N-ethylglycine, beta-aminoisobutyric acid, and norvaline that appear to be extraterrestrial in origin and may provide new evidence for the hypothesis of chemical evolution. Expand
Amino Acid Cosmogeochemistry
Amino acids are ubiquitous components of living organisms and as a result they are widely distributed on the surface of the Earth. Whereas only 20 amino acids are found in proteins, a much moreExpand
Molecular and isotopic analyses of the hydroxy acids, dicarboxylic acids, and hydroxicarboxylic acids of the Murchison meteorite.
Isotopic analyses show these acids to be D-rich relative to terrestrial organic compounds as expected; however, the hydroxy acids appear to be isotopically lighter than the amino acids with respect to both carbon and hydrogen. Expand