Document Detail

Formation of hydroxanthommatin-derived radical in the oxidation of 3-hydroxykynurenine.
MedLine Citation:
PMID:  1314547     Owner:  NLM     Status:  MEDLINE    
Using ESR, a radical (g = 2.004) was detected in the reaction mixture of 3-hydroxykynurenine (3-HKY), H2O2, and horseradish peroxidase. The radical was stable and was detected even after 5 h. On HPLC analysis of the reaction mixture, two radical peaks (Peak-1 and Peak-2) were detected using ESR. The ESR spectra of Peak-1 and Peak-2 radicals were the same and identical with that of the original radical in the reaction mixture. The retention times of Peak-1 and Peak-2 corresponded to those of authentic xanthommatin (XA) and hydroxanthommatin (Hydro-XA), respectively, XA being formed in the oxidation of 3-HKY by potassium ferricyanide and Hydro-XA being formed in the reduction of XA by sodium metabisulfite. The absorbance spectra of Peak-1 and Peak-2 were nearly identical with those of authentic XA and Hydro-XA. The absorbance spectrum of Peak-2 changed from that of Hydro-XA to that of XA, indicating that Hydro-XA auto-oxidized to XA in the air. The ESR signal intensity of the Peak-2 radical developed in accordance with the progress of this auto-oxidation of Hydro-XA to XA. It was supposed that the Peak-2 radical was generated in the auto-oxidation of Hydro-XA after its elution from the HPLC column. Thus, the radical seemed to be the one-electron oxidized form of Hydro-XA. The Peak-1 radical appeared to be the true retention of the radical on the column and to be eluted with a much larger amount of XA. The separation of the radical from XA was impossible on the column. Hemoglobin (Hb) or hematin also induced the same radical in the reaction mixture of 3-KHY, H2O2, and Hb or hematin.
T Ishii; H Iwahashi; R Sugata; R Kido
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Archives of biochemistry and biophysics     Volume:  294     ISSN:  0003-9861     ISO Abbreviation:  Arch. Biochem. Biophys.     Publication Date:  1992 May 
Date Detail:
Created Date:  1992-05-15     Completed Date:  1992-05-15     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0372430     Medline TA:  Arch Biochem Biophys     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  616-22     Citation Subset:  IM    
Department of Biochemistry, Wakayama Medical College, Japan.
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MeSH Terms
Chromatography, High Pressure Liquid
Electron Spin Resonance Spectroscopy
Free Radicals
Hemoglobins / metabolism
Horseradish Peroxidase / metabolism*
Hydrogen Peroxide
Kynurenine / analogs & derivatives*,  chemistry,  metabolism
Oxazines / chemistry*
Time Factors
Reg. No./Substance:
0/Free Radicals; 0/Hemoglobins; 0/Oxazines; 142394-84-1/hydroxanthommatin; 16009-13-5/Hemin; 343-65-7/Kynurenine; 484-78-6/3-hydroxykynurenine; 7722-84-1/Hydrogen Peroxide; EC 1.11.1.-/Horseradish Peroxidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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