Parity-violating energy shifts of Murchison L-amino acids are consistent with an electroweak origin of meteorite L-enantiomeric excesses.
In 1996, four alpha-methyl amino acids in the Murchison meteorite--L-isovaline, L-alpha-methylnorvaline, L-alpha-methyl-allo-isoleucine and L-alpha-methyl-isoleucine--were found to show significant enantiomeric excesses of the L form, ranging from 2% to 9%. Their deuterium to hydrogen isotope ratios suggest they formed in the pre-solar interstellar gas cloud rather than during a later aqueous processing phase on the asteroid parent body. In this paper we apply the techniques of the preceding two papers to compute the parity-violating energy shifts of these amino acids. We find that, in the gas phase, the PVESs of the neutral L forms of all four Murchison alpha-methyl amino acids are decisively negative, and there is even some correlation between the magnitudes of the L-excesses and the magnitudes of the PVESs--all of which is at least consistent with an electroweak origin of the Murchison enantiomeric excesses.
MacDermott
A J
AJ
Department of Chemistry, School of Science, Computing and Engineering, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, TX 77058-1098, USA. macdermott@uhcl.edu
Fu
T
T
Nakatsuka
R
R
Coleman
A P
AP
Hyde
G O
GO
D000596:Amino Acids / Q000737:chemistry*; D008958:Models, Molecular; D013237:Stereoisomerism; D013816:Thermodynamics
D000596:Amino Acids