Inconclusive evidence for nonterrestrial isoleucine enantiomeric excesses in primitive meteorites

Citation:
Elsila, JE, Glavin DP, Dworkin JP, Martins Z, Bada JL.  2012.  Inconclusive evidence for nonterrestrial isoleucine enantiomeric excesses in primitive meteorites. Proceedings of the National Academy of Sciences of the United States of America. 109:E3288-E3288.

Date Published:

Nov

Keywords:

amino-acids

Abstract:

Pizzarello et al. (1) recently described the soluble organic content of eight Antarctic Renazzo-type (CR) carbonaceous chondrites and reported large enantiomeric excesses (ee) of l-isoleucine and d-alloisoleucine. The reported values of ee decrease with inferred increases in aqueous alteration. We believe the conclusions presented in the paper are not fully justified and the data are potentially flawed.

Potential terrestrial contamination of meteoritic amino acid data must always be considered. The manuscript states that “terrestrial contamination levels… were evaluated based on the presence of proteinogenic amino acids’ l-excesses and accounted for when needed,” but this “accounting” is not described. A wide range of l-proteinogenic amino acid excesses was measured …

DOI:

10.1073/pnas.1213261109