Volume 1, Issue 2 (October 2016)

Original research papers

Radiochemistry

REACTIVITY OF SELECTED PRIMITIVE AMINO ACIDS INDUCED BY GAMMA IRRADIATION IN ASTROCHEMICAL CONTEXT

Cristina Cherubini, Ornella Ursini

Pages: 138-142

DOI: 10.21175/RadJ.2016.02.025

Received: 13 MAR 2015, Received revised: 13 APR 2015, Accepted: 20 APR 2015, Published online: 18 OCT 2016

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.
  1. W.H. Sorrell, Origin of amino acids and organic sugars in interstellar clouds. Astrophys. J. Lett., vol 555, pp L129-L132, 2001.
    DOI: 10.1086/322525
  2. E. Anders, N. Grevesse, Abundances of the elements: Meteoritic and solar. Geochim. Cosmochim. Ac., vol 53(1), pp. 197-214, 1989.
    DOI: 10.1016/0016-7037(89)90286-X
  3. T.P. Kohman, Aluminum-26: A nuclide for all seasons. J. Radioanal. Nucl. Chem., vol 219(2), PP. 165-176, 1997.
  4. H.C. Urey, The cosmic abundances of potassium, uranium, and thorium and the heat balances of the Earth, the Moon, and Mars. Proc. Natl Acad. Sci, vol 41(3), pp.127-144, 1955.
    DOI: 10.1073/pnas.41.3.127
  5. H.C. Urey, The cosmic abundances of potassium, uranium, and thorium and the heat balances of the Earth, the Moon, and Mars. Proc. Natl Acad. Sci, vol 42(12), pp. 889-891, 1956.
    DOI: 10.1073/pnas.42.12.889
  6. E. Sagstuen, A. Sanderud, E.O. Hole, The solid-state radiation chemistry of simple amino acids, revisited. Radiat. Res., vol 162(2), pp. 112-119, 2004.
    DOI: 10.1667/RR3215
  7. F. Cataldo, O. Ursini, G. Angelini, Radioracemization and radiation-induced chiral amplification of chiral terpenes measured by optical rotatory dispersion (ORD) spectroscopy. Radiat. Phys. Chem., vol 77 (8), pp. 961-967, 2008.
    DOI: 10.1016/j.radphyschem.2008.03.003
  8. F. Cataldo, G. Angelini, Y. Hafez, S. Iglesias-Groth, Solid state radiolysis of non-proteinaceous amino acids in vacuum: Astrochemical implications. J. Radioanal. Nucl. Chem., vol 295(2), pp.1235-1243, 2013.
    DOI: 10.1007/s10967-012-2167-2
  9. F. Cataldo, P. Ragni, A. Manchado, S. Iglesias-Groth, Solid state radiolysis of amino acids in an astrochemical perspective. Radiat. Phys. Chem., vol 80(1), pp. 57-65, 2011.
    DOI: 10.1016/j.radphyschem.2010.08.012
  10. F. Cataldo, S. Iglesias-Groth, G. Angelini, Y. Hafez, Stability toward high energy radiation of non-proteinogenic amino acids: Implications for the origins of life. Life, vol 3(3), pp. 449-473, 2013.
    DOI: 10.3390/life3030449
  11. C. Cherubini, O. Ursini, F. Cataldo, S. Iglesias-Groth, M.E. Crestoni, Mass spectrometric analysis of selected radiolyzed amino acids in an astrochemical context. J. Radioanal. Nucl. Chem., vol 300(3), pp. 1061-1073, 2014.
    DOI: 10.1007/s10967-014-3078-1
  12. J.R. Cronin, S. Pizzarello, Amino acids in meteorites. Adv. Space Res., vol 3(9), pp. 5-18, 1983.
    DOI: 10.1016/0273-1177(83)90036-4
  13. B. Nordén, J.-O. Liljenzin, R.K. Tokay, Stereoselective decarboxylation of amino acids in the solid state, with special reference to chiral discrimination in prebiotic evolution. J. Mol. Evol., vol 21(4), pp. 364-370, 1985.
    DOI: 10.1007/BF02115656
  14. M. Bonifačić, I. Štefanić, G.L. Hug, D.A. Armstrong, K.D. Asmus, Glycine decarboxylation: The free radical mechanism. J. Am. Chem. Soc., vol 120(38), pp. 9930-9940, 1998.
    DOI: 10.1021/ja9815428
  15. W.A. Bonner, N.E. Blair, R.M. Lemmon, The radioracemization of amino acids by ionizing radiation: Geochemical and cosmochemical implications. Orig. Life, vol 9(4), pp. 279-290, 1979.
    DOI: 10.1007/BF00926821
  16. J.L. Bada, R. Protsch, R.A. Schroeder, The Racemization Reaction of Isoleucine used as a Palaeotemperature Indicator. Nature, vol 241(5389), pp. 394-395, 1973.
    DOI: 10.1038/241394a0