HR: 0800h
AN: B31B-0996    [Abstracts]
TI: Polymerization Experiment Of Amino Acids Under High Pressure And Temperature Conditions Simulating The Deep Lithosphere
AU: * Ohara, S
EM: ohara@ganko.tohoku.ac.jp
AF: Department of Earth and Planetary Materials Scinece, Faculty of Science, Tohoku University , Aramaki-Aza-Aoba, Sendai, 980-8578 Japan
AU: Kakegawa, T
EM: kakegawa@mail.tains.tohoku.ac.jp
AF: Department of Earth and Planetary Materials Scinece, Faculty of Science, Tohoku University , Aramaki-Aza-Aoba, Sendai, 980-8578 Japan
AU: Nakazawa, H
EM: Nakazawa.Hiromoto@nims.go.jp
AF: National Institute for Materials Science, Namiki 1-1, tsukuba, 305-0044 Japan
AB: Chemical evolution in deep sea or deep lithosphere is one of the popular hypotheses for the origin of life on the early Earth. In such hypothesis, effects of pressure and temperature on polymerization (and/or stability) of amino acids needed to be evaluated. In this study, high temperature and pressure experiments were performed using of a test-tube-type autoclave for polymerization of amino acids. Approximately 100 mg of Glycine powder were placed into sterilized gold capsule. Multiple experiments were done at 150 degrees for 1 to 8 days at variable pressures (25MPa, 50MPa, 75MPa and 100MPa). Glycine peptides were identified and quantified by high performance liquid chromatography (HPLC). Each capsule was opened carefully and 1 ml of mobile phase was added to release the amino acids and oligopeptide from the solid phase. Liquid phases were separated by the cetrifugal method. Peptides were identified by retention times of authentic reference substances. The reaction yields were determined as percentage of the reactant converted to the reaction product. Pligopeptides more than hexamer were additionally identified by the detection of the molecular ion by liquid chromatography mass spectrometry (LC / MS). A HPLC chromatogram of the products indicated at least seven oligomers: diketopiperazine (cyc(Gly)2), di-glycine (Gly2), tri-glycine (Gly3), tetra-glycine (Gly4), penta-glycine (Gly5) and hexa-glycine (Gly6). We also identified hepta-glycine (Gly7), octa-glycine (Gly8) and nona-glycine (Gly9) with LC/MS. This is the first report that up to nona-glycine was synthesized under high temperature and pressure conditions. In addition, our experiments indicate that polymerization occurs wide range of pressure from 25 to 100 MPa. On the other hand, yields of total amounts of peptide did not change with pressure, suggesting that an unknown process in the autoclave is limiting the yield. We speculate the activity of water vapor, generated by peptide formation reaction, controlled the yield in the autoclave. The results from this study support the theory that chemical evolution could happen in deep Earth environments, such as inside of lithosphere.
UR: http://www.ganko.tohoku.ac.jp
DE: 0420 Biomolecular and chemical tracers
SC: Biogeosciences [B]
MN: Fall Meeting 2005