title: Amino acids of the Murchison meteorite:  II.  Five carbon acyclic primary beta-, gamma-, and delta-amino alkanoic acids.
abstract: All ten of the possible five-carbon acyclic primary beta-, gamma-, and delta-amino alkanoic acids (amino position isomers of the valines) have been positively identified in hot-water extracts of the Murchison meteorite using combined gas chromatography-mass spectrometry (GC-MS) and ion exchange chromatography.  With the exception of delta-aminovaleric acid, none of these amino acids has been previously reported to occur in meteorites or in any other natural material.  The gamma-amino acids (4-aminopentanoic acid, 4-amino-2-methlybutanoic acid, and 4-amino-3-methylbutanoic acid) are present at higher concentrations (about 5 nmol g-1)than are the beta-amino isomers (3-aminopentanoic acid, 3-amino-2-methylbutanoic acid, allo-3-amino-2-methylbutanoic acid, 3-amino-3-methylbutanoic acid, 3-amino-2-ethylpropanoic acid, and 3-amino-2,2-dimethylpropanoic acid) which are present at concentrations of 1-2 nmol g-1.  These amino acids are less abundant in the meteorite than either the corresponding alpha-amino acids or the four-carbon homologues.  Thirty-six amino acids have now been positively identified in the Murchison meteorite, 17 of which are apparently unique to carbonaceous chondrites.  The fact that the meteorite contains all possible five-carbon acyclic primary alpha-, beta-, gamma-, and delta-amino alkanoic acids is consistent with a synthetic process involving random combination of single-carbon precursors.
authors.affiliation: Department of Chemistry, Arizona State University, Tempe 85287, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Cronin
authors.forename: S
authors.initials: S
authors.lastname: Pizzarello
authors.forename: G U
authors.initials: GU
authors.lastname: Yuen
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D002852:Chromatography, Ion Exchange; D006358:Hot Temperature; D007536:Isomerism; D019110:Meteoroids; D014633:Valine / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D000596:Amino Acids; C032737:isovaline; C005313:norvaline; D014633:Valine