REACTIVITY OF SELECTED PRIMITIVE AMINO ACIDS INDUCED BY GAMMA IRRADIATION IN ASTROCHEMICAL CONTEXT
Cristina Cherubini, Ornella Ursini
Received: 13 MAR 2015,
Received revised: 13 APR 2015,
Accepted: 20 APR 2015,
Published online: 18 OCT 2016
Full Text (PDF)
Amino acids in meteorites were preserved from the action of high energy sources (cosmic rays and ultraviolet protons) by their collocation, at a depth of 20 m. At the same time, the presence of radioactive elements was the cause of amino acids’ degradation. The radioactive elements produced a total radiation dose of 14 MGy during the life of the Solar System (4.6x109 years). Aside from the amino acids’ degradation, radiations promoted a radioracemization process that was able to reduce the L-enantiomeric excess of amino acids. Our studies are aimed at identifying the radiation products formed in a solid state radiolysis using mass spectrometric techniques. Moreover, we are analyzing the radioracemization process at different irradiation conditions for proteinogenic and non proteinogenic amino acids. The amino acids show a relevant radiation and radioracemization resistance, especially the proteinaceous ones, such as leucine, valine and isoleucine. Some identified degradation pathways are significant due to their final products which can be considered precursors of more complex intermediates.
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