Document Detail


Formation of oxygen radicals in solutions of 7,8-dihydroneopterin.
MedLine Citation:
PMID:  10527875     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Neopterin and 7,8-dihydroneopterin, two compounds which are secreted by activated macrophages, have been shown to interfere with radicals generated by cellular and certain chemical systems. Reduced pterins were reported to scavenge whereas aromatic pterins promoted or reduced radical mediated reactions or had no effect. However, recently it was found that high concentrations of 7, 8-dihydroneopterin enhanced luminol dependent chemiluminescence and T-cell apoptosis, suggesting an enhancement of free radical formation. In this study hydroxylation of salicylic acid was used for detection of hydroxyl radicals. It is shown that in solutions of 7,8-dihydroneopterin hydroxyl radicals were formed in the absence of any radical source. The presence of EDTA chelated iron enhanced hydroxyl radical formation. Whereas the addition of iron accelerated the hydroxylation reaction, 7,8-dihydroneopterin was responsible for the amount of hydroxylation products. In the presence of superoxide dismutase or catalase, as well as by helium purging, hydroxylation was inhibited. Our data suggest that in solutions of 7, 8-dihydroneopterin superoxide radicals are generated which are converted to hydroxyl radicals by Fenton or Haber-Weiss type reactions. While superoxide might be generated during autoxidation of ferrous iron, dihydroneopterin seems to be involved in regeneration of ferrous iron from the ferric form.
Authors:
K Oettl; B Wirleitner; G Baier-Bitterlich; T Grammer; D Fuchs; G Reibnegger
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochemical and biophysical research communications     Volume:  264     ISSN:  0006-291X     ISO Abbreviation:  Biochem. Biophys. Res. Commun.     Publication Date:  1999 Oct 
Date Detail:
Created Date:  1999-11-12     Completed Date:  1999-11-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372516     Medline TA:  Biochem Biophys Res Commun     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  262-7     Citation Subset:  IM    
Copyright Information:
Copyright 1999 Academic Press.
Affiliation:
Institute for Medical Chemistry and Pregl Laboratory, Karl-Franzens-University Graz, Harrachgasse 21/II, Graz, A-8010, Austria.
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MeSH Terms
Descriptor/Qualifier:
Catalase / metabolism
Chromatography, High Pressure Liquid
Edetic Acid / chemistry
Hydroxyl Radical / metabolism*
Hydroxylation
Iron / chemistry
Neopterin / metabolism
Oxygen / metabolism*
Pteridines / metabolism*
Superoxide Dismutase / metabolism
Superoxides / metabolism
Chemical
Reg. No./Substance:
0/Pteridines; 11062-77-4/Superoxides; 1218-98-0/7,8-dihydroneopterin; 3352-57-6/Hydroxyl Radical; 60-00-4/Edetic Acid; 670-65-5/Neopterin; 7439-89-6/Iron; 7782-44-7/Oxygen; EC 1.11.1.6/Catalase; EC 1.15.1.1/Superoxide Dismutase

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


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