Abstract
Hydroxyl radicals (OH.) in free solution react with scavengers at rates predictable from their known second-order rate constants. However, when OH. radicals are produced in biological systems by metal-ion-dependent Fenton-type reactions scavengers do not always appear to conform to these established rate constants. The detector molecules deoxyribose and benzoate were used to study damage by OH. involving a hydrogen-abstraction reaction and an aromatic hydroxylation. In the presence of EDTA the rate constant for the reaction of scavengers with OH. was generally higher than in the absence of EDTA. This radiomimetic effect of EDTA can be explained by the removal of iron from the detector molecule, where it brings about a site-specific reaction, by EDTA allowing more OH. radicals to escape into free solution to react with added scavengers. The deoxyribose assay, although chemically complex, in the presence of EDTA appears to give a simple and cheap method of obtaining rate constants for OH. reactions that compare well with those obtained by using pulse radiolysis.
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Selected References
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- Baker M. S., Gebicki J. M. The effect of pH on the conversion of superoxide to hydroxyl free radicals. Arch Biochem Biophys. 1984 Oct;234(1):258–264. doi: 10.1016/0003-9861(84)90348-5. [DOI] [PubMed] [Google Scholar]
- Cederbaum A. I., Dicker E., Rubin E., Cohen G. Effect of thiourea on microsomal oxidation of alcohols and associated microsomal functions. Biochemistry. 1979 Apr 3;18(7):1187–1191. doi: 10.1021/bi00574a011. [DOI] [PubMed] [Google Scholar]
- Goldstein S., Czapski G. Mannitol as an OH. scavenger in aqueous solutions and in biological systems. Int J Radiat Biol Relat Stud Phys Chem Med. 1984 Dec;46(6):725–729. doi: 10.1080/09553008414551961. [DOI] [PubMed] [Google Scholar]
- Grootveld M., Halliwell B. An aromatic hydroxylation assay for hydroxyl radicals utilizing high-performance liquid chromatography (HPLC). Use to investigate the effect of EDTA on the Fenton reaction. Free Radic Res Commun. 1986;1(4):243–250. doi: 10.3109/10715768609051634. [DOI] [PubMed] [Google Scholar]
- Gutteridge J. M. Ferrous ion-EDTA-stimulated phospholipid peroxidation. A reaction changing from alkoxyl-radical- to hydroxyl-radical-dependent initiation. Biochem J. 1984 Dec 15;224(3):697–701. doi: 10.1042/bj2240697. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gutteridge J. M. Reactivity of hydroxyl and hydroxyl-like radicals discriminated by release of thiobarbituric acid-reactive material from deoxy sugars, nucleosides and benzoate. Biochem J. 1984 Dec 15;224(3):761–767. doi: 10.1042/bj2240761. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gutteridge J. M. Thiobarbituric acid-reactivity following iron-dependent free-radical damage to amino acids and carbohydrates. FEBS Lett. 1981 Jun 15;128(2):343–346. doi: 10.1016/0014-5793(81)80113-5. [DOI] [PubMed] [Google Scholar]
- Gutteridge J. M., Toeg D. Iron-dependent free radical damage to DNA and deoxyribose. Separation of TBA-reactive intermediates. Int J Biochem. 1982;14(10):891–893. doi: 10.1016/0020-711x(82)90071-4. [DOI] [PubMed] [Google Scholar]
- Halliwell B., Gutteridge J. M. Formation of thiobarbituric-acid-reactive substance from deoxyribose in the presence of iron salts: the role of superoxide and hydroxyl radicals. FEBS Lett. 1981 Jun 15;128(2):347–352. doi: 10.1016/0014-5793(81)80114-7. [DOI] [PubMed] [Google Scholar]
- Moorhouse C. P., Halliwell B., Grootveld M., Gutteridge J. M. Cobalt(II) ion as a promoter of hydroxyl radical and possible 'crypto-hydroxyl' radical formation under physiological conditions. Differential effects of hydroxyl radical scavengers. Biochim Biophys Acta. 1985 Dec 13;843(3):261–268. doi: 10.1016/0304-4165(85)90147-3. [DOI] [PubMed] [Google Scholar]
- Sagone A. L., Jr, Decker M. A., Wells R. M., Democko C. A new method for the detection of hydroxyl radical production by phagocytic cells. Biochim Biophys Acta. 1980 Feb 21;628(1):90–97. doi: 10.1016/0304-4165(80)90354-2. [DOI] [PubMed] [Google Scholar]
- Van Hemmen J. J., Meuling W. J. Inactivation of biologically active DNA by gamma-ray-induced superoxide radicals and their dismutation products singlet molecular oxygen and hydrogen peroxide. Biochim Biophys Acta. 1975 Aug 21;402(2):133–141. doi: 10.1016/0005-2787(75)90031-3. [DOI] [PubMed] [Google Scholar]
- Winston G. W., Cederbaum A. I. Oxidative decarboxylation of benzoate to carbon dioxide by rat liver microsomes: a probe for oxygen radical production during microsomal electron transfer. Biochemistry. 1982 Aug 31;21(18):4265–4270. doi: 10.1021/bi00261a013. [DOI] [PubMed] [Google Scholar]