Evaluation of the Reactivity of L-tyrosine in the T-for-H Exchange Reaction at Low Temperature

• KATAOKA Noriaki

  Graduate School of Science and Technology, Niigata University

• KANDA Naoyuki

  Graduate School of Science and Technology, Niigata University

• IMAIZUMI Hiroshi

  Department of Chemistry and Chemical Engineering, Faculty of Engineering, Niigata University

• KANO Naoki

  Department of Chemistry and Chemical Engineering, Faculty of Engineering, Niigata University

Abstract

In order to quantitatively evaluate the internal exposure of tritium(³H or T), both the reactivity of exchangeable and non‐exchangeable Organically Bound Tritium(OBT) must be observed at body temperature. In this study, we assumed the model of exchangeable OBT, and the hydrogen isotope exchange reaction(T-for-H exchange reaction) between L-tyrosine and HTO vapor was observed at 25 and 36 ℃ in the gas-solid system. Applying the A″-McKay plot method to the data obtained in the reaction, the rate constants(k) of the functional groups in the material were obtained and Arrhenius plots were also drawn. In addition, from the Arrhenius plots in the range of 50 - 70 ℃, the estimated rate constants(k_ex) of 36 and 25 ℃ were obtained by using extrapolation method. Comparing k and k_ex, following three matters have been found in the T-for-H exchange reaction. (1)Because the value of k was similar to k_ex, extrapolation method is useful. (2)Applying Taft's equation, polar and steric substituent constants of C₇H₇O were obtained. (3)The method used in this work is useful for quantitative clarification of the reactivity of the T-for-H exchange reaction, and for the estimation of the internal exposure of exchangeable OBT.

Journal

• RADIOISOTOPES

  RADIOISOTOPES 63 (9), 429-434, 2014

  Japan Radioisotope Association

Keywords

• T-for-H exchange reaction
• A″-McKay plot method
• exchangeable organically bound tritium
• L-tyrosine
• rate constant
• Taft's plot
• estimation of extrapolated rate constant

Details

• CRID: 1390001204156413184
• NII Article ID: 130004691281
• NII Book ID: AN00351589
• DOI: 10.3769/radioisotopes.63.429
• ISSN: 18844111
• ISSN: 00338303
• NDL BIB ID: 025808699
• Web Site: http://id.ndl.go.jp/bib/025808699
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I025808699
• Web Site: https://www.jstage.jst.go.jp/article/radioisotopes/63/9/63_429/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed