AN ESR STUDY OF AMINO ACID AND PROTEIN FREE RADICALS IN SOLUTION PART I. Reaction Mechanism of Free Radical Production in the Ti-$H_2O_2$ Flow System

용액에서의 아미노산 및 단백질 자유기에 관한 ESR 연구 제1보 ; Ti-$H_2O_2$ Flow System에서 자유기를 만드는 반응기구

  • Hong Sun-Joo (Department of Biochemistry and Biophysics, University of Hawaii) ;
  • L. H. Piette (Department of Biochemistry and Biophysics, University of Hawaii)
  • 홍순주 (미국 하와이 대학교 생화학 및 생물리학과) ;
  • Published : 19710230

Abstract

The reaction of amino acids and the reactive hydroxyl radical generated by $Ti^{3+}-H_2O_2$ system was studied using fast flow techniques coupled with ESR. Upon adding methionine to the 0.2M $H_2O_2$ solution (0.05M methionine after addition) and mixing with 0.01M $TiCl_3$, the low field component of the two incompletely resolved peaks, in the spectrum of $Ti^{3+}-H_2O_2$ system alone, vanished completely whereas the high field component remained almost constant and superimposed on the secondary spectrum of the methionine free radical. Similar results were obtained for other amino acids and proteins. The results strongly demonstrate that the $T^{3+}-H_2O_2$ flow system generates two different radical species, only one of which, giving rise to the low field component, is alone responsible for abstracting hydrogen atoms from substrate molecules. The effects of HCl, $H_2SO_4$ and NaOH on the system were also studied with widely varying results.

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