The radioracemization of isovaline. Cosmochemical implications

William A. Bonner*, Neal E. Blair, Richard M. Lemmon, Jose J. Flores, Glenn E. Pollock

*Corresponding author for this work

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

The optically pure d- and l-enantiomers of isovaline (I), which cannot be racemized by ordinary chemical mechanisms involving α-hydrogen removal, and which has been isolated in apparently racemic form from the Murchison meteorite, have been subjected to partial radiolysis by the ionizing radiation from a 3000 Ci 60Co γ-ray source. Both in the anhydrous and hydrated solid states and as solid sodium or hydrochloride salts each enantiomer suffered significant radioracemization of the undestroyed residue during its partial radiolysis. The sodium salt of isovaline in 0.1 M aqueous solution suffered extensive radiolysis with relatively small radiation doses, but showed no detectable radioracemization. The significance of these observations with respect to the primordial enantiomeric composition of the isovaline (and other amino acids) indigenous to meteroties is discussed.

Original languageEnglish (US)
Pages (from-to)1841-1846
Number of pages6
JournalGeochimica et Cosmochimica Acta
Volume43
Issue number11
DOIs
StatePublished - Nov 1979

ASJC Scopus subject areas

  • Geochemistry and Petrology

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