Acta Phys. -Chim. Sin. ›› 2002, Vol. 18 ›› Issue (09): 812-816.doi: 10.3866/PKU.WHXB20020909

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Solvent Effects on the Oxidation of TyrOH by SO4●－ Radical

Chu Gao-Sheng;Zhang Shu-Juan;Yao Si-De;Dou Da-Ying;Zhang Zhi-Cheng   

  1. Department of Applied Chemistry, University of Science and Technology of China, Hefei　230026; Laboratory of Radiation Chemistry, Shanghai Institute of Nuclear Research, Chinese Academy of Sciences, P.O.Box 800-204,Shanghai　201800
  • Received:2001-11-23 Revised:2002-05-27 Published:2002-09-15
  • Contact: Chu Gao-Sheng E-mail:gschu@ustc.edu.cn

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Abstract: This work presents the study on the oxidation of TyrOH by SO4●－ in water/ACN mixed media. Investigations show that the reaction mechanism between TyrOH and SO4●－ does not change by the addition of ACN, whereas the kinetic behavior of the transient species produced is significantly affected. The decay of SO4●－ decelerates with increasing volume fraction of ACN in mixed media whereas the decay of TyrO● accelerates. We suggest that the contrary effects of the solvent on the decay of both SO4●－ and TyrO● are due to their different charges. The deceleration of the oxidation of TyrOH by SO4●－ with the increase of ACN fraction may demonstrate that in the presence of organic solvents the redox potential of TyrO●/TyrOH is altered, which provides support for the suggestion that the redox potential of TyrO●/ TyrOH might be altered with their inclusion into peptides and proteins.

Key words: TyrOH, SO4●－ radical, Redox potential, Solvent effect, Acetonitrile(ACN)