Distribution and enantiomeric composition of amino acids in the Murchison meteorite

  title={Distribution and enantiomeric composition of amino acids in the Murchison meteorite},
  author={Michael H. Engel and Bartholomew S. Nagy},
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) and pseudoleucine (Ple), as well as common ones such as glycine (Gly), alanine (Ala) and glutamic acid (Glu)1–10. Amino acids that could be resolved into their respective D- and L-enantiomers were reported to be racemic (see, for example, refs 1, 3, 5), although small sample size might have hindered the precise… Expand
On the reported optical activity of amino acids in the Murchison meteorite
In analyses of extracts from the Murchison meteorite (a carbonaceous chondrite), Engel and Nagy1 reported an excess of L-enantiomers for several protein amino acids but found that the non-proteinExpand
Enantiomeric Excesses in Meteoritic Amino Acids
Gas chromatographic-mass spectral analyses of the four stereoisomers of 2-amino-2,3-dimethylpentanoic acid obtained from the Murchison meteorite show that the L enantiomer occurs in excess, indicative of an asymmetric influence on organic chemical evolution 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
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
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
The stereochemistry of amino acids in the Murchison meteorite
Abstract The questions of how, where and when life originated in our solar system remain largely unanswered. Some advances have been made with respect to abiotic synthesis of the key molecules deemedExpand
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
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
Stable isotope analysis of amino acid enantiomers in the Murchison meteorite at natural abundance levels
The ability to determine the stable carbon and nitrogen isotope compositions of individual amino acid enantiomers in carbonaceous meteorites can provide insights with respect to their origin(s) andExpand
A comparative study of the hydroxy acids from the Murchison, GRA 95229 and LAP 02342 meteorites
Abstract The hydroxy acid suites extracted from the Murchison (MN), GRA 95229 (GRA) and LAP 02342 (LAP) meteorites have been investigated for their molecular, chiral and isotopic composition.Expand


Determination of the D and L isomers of some protein amino acids present in soils.
It was found that very significant amounts of D-alanine, D-aspartic acid, and D-glutamic acid were present in the contemporary soils studied and indicated that the determination of D and L percentages requires amino acid purification if one is to obtain accurate data. Expand
A review of the geochemical applications of the amino acid racemization reaction
Abstract A method of geochronology based on the chemical racemization of amino acids has been developed within the last few years. The various amino acids that make up the proteins of all livingExpand
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-acids, Aliphatic and Aromatic Hydrocarbons in the Murchison Meteorite
The Murchison meteorite, a type III carbonaceous chondrite, contains substantial amounts of amino-acids, predominantly cyclic aliphatic hydrocarbons, which are consistent with the appreciable content of carbon and nitrogen of this meteorite. Expand
Amino acids in the Murchison meteorite
Abstract Continued investigation of the Murchison meteorite by gas chromatography combined with mass spectrometry has led to the characterization of at least 17 amino acids in addition to the 18Expand
Stereoisomers of isovaline in the Murchison meteorite
Abstract Isovaline is present in the Murchison meteorite as a racemic mixture (about equal concentrations of the R and S enantiomers). Since isovaline does not have a hydrogen atom on its asymmetricExpand
Kinetics of amino acid racemization in Sequoiadendron giganteum heartwood.
An average temperature which the bound aspartic acid in sequoia had experienced during the past ∼2200 years was obtained, which agrees with modern temperatures near the sample location and estimated paleotemperatures during the Past ∼2000 years. Expand
Amino acids and hydrocarbons ∼3,800-Myr old in the Isua Rocks, southwestern Greenland
The Isua supracrustal belt consists of metamorphic rocks, including metamorphosed sediments, and are the oldest known rocks on Earth. It has been postulated1,2 that hydrocarbons recently detected inExpand
Carbon, hydrogen and nitrogen isotopes in solvent-extractable organic matter from carbonaceous chondrites
Solvent extractions were done on the carbonaceous chondrites Murray, Murchison, Orgueil and Renazzo, using CCl_4 and CH_3OH. Between 2 and 10% of the total carbon in these meteorites is extractableExpand
L Amino acids and D-glucose bind stereospecifically to a colloidal clay.
It is suggested that this difference between stereoisomers could account for the evolution of life forms possessing a great preponderance of L amino acids and D-glucose. Expand