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Formation of oxygen radicals in solutions of 7,8-dihydroneopterin.
Biochem Biophys Res Commun. 1999 Oct 14; 264(1):262-7.BB

Abstract

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+Show Affiliations

Institute for Medical Chemistry and Pregl Laboratory, Karl-Franzens-University Graz, Harrachgasse 21/II, Graz, A-8010, Austria.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10527875

Citation

Oettl, K, et al. "Formation of Oxygen Radicals in Solutions of 7,8-dihydroneopterin." Biochemical and Biophysical Research Communications, vol. 264, no. 1, 1999, pp. 262-7.
Oettl K, Wirleitner B, Baier-Bitterlich G, et al. Formation of oxygen radicals in solutions of 7,8-dihydroneopterin. Biochem Biophys Res Commun. 1999;264(1):262-7.
Oettl, K., Wirleitner, B., Baier-Bitterlich, G., Grammer, T., Fuchs, D., & Reibnegger, G. (1999). Formation of oxygen radicals in solutions of 7,8-dihydroneopterin. Biochemical and Biophysical Research Communications, 264(1), 262-7.
Oettl K, et al. Formation of Oxygen Radicals in Solutions of 7,8-dihydroneopterin. Biochem Biophys Res Commun. 1999 Oct 14;264(1):262-7. PubMed PMID: 10527875.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Formation of oxygen radicals in solutions of 7,8-dihydroneopterin. AU - Oettl,K, AU - Wirleitner,B, AU - Baier-Bitterlich,G, AU - Grammer,T, AU - Fuchs,D, AU - Reibnegger,G, PY - 1999/10/21/pubmed PY - 1999/10/21/medline PY - 1999/10/21/entrez SP - 262 EP - 7 JF - Biochemical and biophysical research communications JO - Biochem Biophys Res Commun VL - 264 IS - 1 N2 - 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. SN - 0006-291X UR - https://www.unboundmedicine.com/medline/citation/10527875/Formation_of_oxygen_radicals_in_solutions_of_78_dihydroneopterin_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006-291X(99)91520-6 DB - PRIME DP - Unbound Medicine ER -