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52
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Gutteridge JM. Iron and oxygen: a biologically damaging mixture. ACTA PAEDIATRICA SCANDINAVICA. SUPPLEMENT 1989; 361:78-85. [PMID: 2485589 DOI: 10.1111/apa.1989.78.s361.78] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Iron is a remarkably useful metal in Nature, but iron ions not safely sequestered in storage or transport proteins are hazardous because they can stimulate damaging free radical reactions. Biological examples of these are Fenton Chemistry leading to the formation of highly reactive species, such as the hydroxyl radical (.OH) and the ferryl ion (FeO2+), and lipid peroxidation. The need to conserve body iron stores has closely evolved with an essential requirement for antioxidant protection and, several 'acute-phase' proteins involved in iron metabolism such as caeruloplasmin, haptoglobins and haemopexin in collaboration with the iron binding proteins transferrin and lactoferrin contribute to our defense against oxidative damage.
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Affiliation(s)
- J M Gutteridge
- Molecular Toxicology Research Group, Oklahoma Medical Research Foundation, Oklahoma City 73104
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53
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Flitter WD, Mason RP. The spin trapping of pyrimidine nucleotide free radicals in a Fenton system. Biochem J 1989; 261:831-9. [PMID: 2552992 PMCID: PMC1138906 DOI: 10.1042/bj2610831] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The reaction of the hydroxyl radical, generated by a Fenton system, with pyrimidine deoxyribonucleotides was investigated by using the e.s.r. technique of spin trapping. The spin trap t-nitrosobutane was employed to trap secondary radicals formed by the reaction of the hydroxyl radical with these nucleotides. The results presented here show that hydroxyl-radical attack on thymidine, 2-deoxycytidine 5-monophosphate and 2-deoxyuridine 5-monophosphate produced nucleotide-derived free radicals. The results indicate that .OH radical attack occurs predominantly at the carbon-carbon double bond of the pyrimidine base. The e.s.r. studies showed a good correlation with previous results obtained by authors who used x- or gamma-ray irradiation to generate the hydroxyl radical. A thiobarbituric acid assay was also used to monitor the damage produced to the nucleotides by the Fenton system. These results showed qualitative agreement with the spin-trapping studies.
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Affiliation(s)
- W D Flitter
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
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54
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Rahhal S, Richter HW. Reaction of hydroxyl radicals with the ferrous and ferric iron chelates of diethylenetriamine-N,N,N',N",N"- pentaacetate. FREE RADICAL RESEARCH COMMUNICATIONS 1989; 6:369-77. [PMID: 2551794 DOI: 10.3109/10715768909087920] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Reactions of the hydroxyl radical with ferrous and ferric diethylenetriamine-N,N,N',N",N"-pentaacetate (DTPA) complexes in neutral aqueous solution were studied using a 60Co-gamma radiolysis source for radical production. Hydroxyl radicals oxidize the ferrous chelate of DTPA to the ferric chelate, as determined by changes in the optical absorbance. In the presence of equimolar concentrations of ferric and ferrous chelates, HO. is "trapped" by Fe(III)DTPA2- and yields of Fe(III)DTPA2- are substantially reduced. Both tert-butyl alcohol and methanol react efficiently with hydroxyl radicals. tert-Butyl alcohol produces unreactive radicals, and is thus an effective scavenger. However, the reducing hydroxymethyl radical produced upon reaction of HO. with methanol effectively reduces Fe(III)DTPA2- present in the system, so that solutions initially containing the more absorbing Fe(III)DTPA2- are bleached. These results with alcoholic hydroxyl radical scavengers illustrate possible complications from scavengers such as methanol which produce reactive products which may themselves stimulate further reaction.
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Affiliation(s)
- S Rahhal
- Department of Chemistry, University of Akron, Ohio 44325
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55
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Sutton HC, Winterbourn CC. On the participation of higher oxidation states of iron and copper in Fenton reactions. Free Radic Biol Med 1989; 6:53-60. [PMID: 2536343 DOI: 10.1016/0891-5849(89)90160-3] [Citation(s) in RCA: 209] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- H C Sutton
- Institute of Nuclear Sciences, Department of Scientific and Industrial Research, Lower Hutt, New Zealand
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56
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Tachon P. Ferric and cupric ions requirement for DNA single-strand breakage by H2O2. FREE RADICAL RESEARCH COMMUNICATIONS 1989; 7:1-10. [PMID: 2509299 DOI: 10.3109/10715768909088155] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hydrogen peroxide (H2O2), was able to nick the replicative form of the phage fd, without the addition of a reducing agent or of a metal. This DNA single-strand breakage decreased with an increase of the ionic strength, suggesting that H2O2 reacted with traces of metal bound to DNA. When cupric of ferric ions were added, the rate of DNA single-strand breakage by H2O2 greatly increased and it was 20-30 times faster with cupric than with ferric ions. The addition of EDTA at an equimolar ratio or in excess of metal prevented partially DNA single-strand cleavage by H2O2 in the presence of ferric ions and completely when cupric ions were used. Superoxide dismutase prevented DNA single-strand breakage by H2O2 and ferric ions. On the contrary, with cupric ions and H2O2, the addition of superoxide dismutase increased the rate of DNA single-strand breakage. That superoxide dismutase was acting catalytically was shown by the loss of its effects after heat inactivation of the enzyme. The results of the present study show that besides its involvement in the Fenton reaction, H2O2 is able to reduce the metal bound to DNA, generating the superoxide anion radical or/and its protonated form, the perhydroxyl radical involved in DNA nicking. On the other hand, the ability of cuprous ions unlike ferrous ions to dismutate the superoxide radical may explain some differences observed between iron and copper in the DNA single-strand breakage by H2O2.
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Affiliation(s)
- P Tachon
- Laboratoires de Recherche Fondamentale de l'Oreal, Aulnay-sous-Bois, France
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57
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Czapski G, Goldstein S, Meyerstein D. What is unique about superoxide toxicity as compared to other biological reductants? A hypothesis. FREE RADICAL RESEARCH COMMUNICATIONS 1988; 4:231-6. [PMID: 2852624 DOI: 10.3109/10715768809055147] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Usually the toxicity of superoxide is attributed to its ability to reduce metal ions and subsequently reoxidation of the metal by hydrogen peroxide yields deleterious oxidizing species. As many other nontoxic biological reductants reduce metal compounds, we suggest that part of the mechanism of superoxide toxicity results from its ability to oxidize metal ions bound to biological targets, which subsequently degrade the target via an intramolecular electron transfer reaction.
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Affiliation(s)
- G Czapski
- Department of Physical Chemistry, Hebrew University of Jerusalem, Israel
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58
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Abstract
In a wide variety of biological systems non-enzyme complexes of the metals copper (Cu) and iron (Fe) have been shown to enhance oxygen radical damage by increasing the production of an oxidative species generally believed to be the hydroxyl free radical (.OH) via "Fenton" and possibly "Haber-Weiss" type reactions. However, the behavior of the chemically and biologically similar transition metal manganese (Mn) with .OH is unknown. Unlike Fe and Cu, inorganic complexes of Mn are known to exist in high concentrations in certain cells. Three different oxygen free radical generating systems and four .OH detection methods were used to investigate the activity of biologically relevant inorganic Mn complexes. These complexes were compared to compounds reported to scavenge and generate .OH. The direct and indirect effects of Mn on the .OH flux were compared by attempting to distinguish the effects of hydrogen peroxide (H2O2), superoxide (O2-), and .OH through the use of selective scavengers and generators. Mn-EDTA and biologically relevant Mn-pyrophosphates and polyphosphates, in contrast to Fe-EDTA, do not generate .OH in these systems. The results suggest that Mn in various forms does, indeed, inhibit oxy-radical damage mediated by .OH, but only if the .OH production is dependent on the presence of O2- or H2O2. Thus, with .OH, as with O2- and H2O2, Mn complexes appear to behave in a fundamentally different fashion from Cu and Fe.
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Affiliation(s)
- P L Cheton
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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59
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Harel S, Salan MA, Kanner J. Iron release from metmyoglobin, methaemoglobin and cytochrome c by a system generating hydrogen peroxide. FREE RADICAL RESEARCH COMMUNICATIONS 1988; 5:11-9. [PMID: 2853113 DOI: 10.3109/10715768809068554] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The reaction of H2O2 with resting metmyoglobin (MetMb), methaemoglobin (MetHb) and cytochrome-c (Cyt-c) was studied in the Soret and visible regions. The differences between the original and the final peak heights of the native haemproteins at 408 nm was found to be directly proportional to the loss of iron from the molecule. The release of iron from haemproteins was studied in a system generating H2O2 continuously at a low rate by an enzymic system, or by addition of large amounts of H2O2. Cytochrome-c, methaemoglobin and metmyoglobin during interaction with H2O2 at a concentration of 200 microM release 40%, 20% and 3%, respectively, of molecular iron after 10 min. The inhibition of haem degradation and iron release by enzymatically-generated H2O2 was determined using several hydroxyl radical scavengers, reducing agents and antioxienzymes, such as superoxide dismutase, catalase and caeruloplasmin.
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Affiliation(s)
- S Harel
- Agricultural Research Organization, Volcani Center, Department of Food Science, Bet-Dagan, Israel
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60
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Affiliation(s)
- B H Bielski
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
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61
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Albano E, Tomasi A, Goria-Gatti L, Dianzani MU. Spin trapping of free radical species produced during the microsomal metabolism of ethanol. Chem Biol Interact 1988; 65:223-34. [PMID: 2837334 DOI: 10.1016/0009-2797(88)90108-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Liver microsomes incubated with a NADPH regenerating system, ethanol and the spin trapping agent 4-pyridyl-1-oxide-t-butyl nitrone (4-POBN) produced an electron spin resonance (ESR) signal which has been assigned to the hydroxyethyl free radical adduct of 4-POBN by using 13C-labelled ethanol. The free radical formation was dependent upon the activity of the microsomal monoxygenase system and increased following chronic feeding of the rats with ethanol. The production of hydroxyethyl free radicals was stimulated by the addition of azide, while catalase and OH. scavengers decreased it. This suggested that hydroxyl radicals (OH.) produced in a Fenton-type reaction from endogenously formed hydrogen peroxide were involved in the free radical activation of ethanol. Consistently, the supplementation of iron, under various forms, also increased the intensity of the ESR signal which, on the contrary, was inhibited by the iron-chelating agent desferrioxamine. Microsomes washed with a solution containing desferrioxamine and incubated in a medium treated with Chelex X-100 in order to remove contaminating iron still produced hydroxyethyl radicals, although at a reduced rate. Under these conditions the free radical formation was apparently independent from the generation of OH. radicals, whereas addition of cytochrome P-450 inhibitors decreased the hydroxyethyl radical formation, suggesting that a cytochrome P-450-mediated process might also be involved in the activation of ethanol. Reduced glutathione (GSH) was found to effectively scavenge the hydroxyethyl radical, preventing its trapping by 4-POBN. The data presented suggest that ethanol-derived radicals could be generated during the microsomal metabolism of alcohol probably through two different pathways. The detection of ethanol free radicals might be relevant in understanding the pathogenesis of the liver lesions which are a consequence of alcohol abuse.
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Affiliation(s)
- E Albano
- Dipartimento di Medicina ed Oncologia Sperimentale, Università di Torino, Italy
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62
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Buettner GR. 1018 - ACTIVATION OF OXYGEN BY METAL COMPLEXES AND ITS RELEVANCE TO AUTOXIDATIVE PROCESSES IN LIVING SYSTEMS. JOURNAL OF ELECTROANALYTICAL CHEMISTRY AND INTERFACIAL ELECTROCHEMISTRY 1987; 18:29-36. [PMID: 25484449 PMCID: PMC4257492 DOI: 10.1016/0302-4598(87)85005-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aspects of the kinetics and thermodynamics of the iron-catalysed Haber-Weiss reaction are discussed with special emphasis on the potential in vivo sources of iron. In addition, the properties of the iron chelates that inhibit the Haber-Weiss reaction are considered.
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Affiliation(s)
- Garry R Buettner
- GSF Forschungszenirum, Institut für Strahlenbiologie, D-8042 Neuherberg (F.R.G.)
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63
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Braughler JM, Chase RL, Pregenzer JF. Oxidation of ferrous iron during peroxidation of lipid substrates. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 921:457-64. [PMID: 3117117 DOI: 10.1016/0005-2760(87)90072-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Oxidation of Fe2+ in solution was dependent upon medium composition and the presence of lipid. The complete oxidation of Fe2+ in 0.9% saline was markedly accelerated in the presence of phosphate or EDTA and the ferrous oxidation product formed was readily recoverable as Fe2+ by ascorbate reduction. In contrast, in the presence of either brain synaptosomal membranes, phospholipid liposomes, fatty acid micelles or H2O2, less than 50% of the Fe2+ oxidized during an incubation could be recovered as Fe2+ via reduction with ascorbate. In the presence of unsaturated lipid, oxidation of Fe2+ was associated with peroxidation of lipid, as assessed by the uptake of O2 and formation of thiobarbituric acid-reactive products during incubations. Although relatively little Fe2+ oxidation or lipid peroxidation occurred in saline with synaptosomes or linoleic acid micelles during an incubation with Fe2+ alone, significant Fe2+ oxidation and lipid peroxidation occurred in incubations containing a 1:1 ratio of Fe2+ and Fe3+. Extensive Fe2+ oxidation and lipid peroxidation also occurred with Fe2+ alone in saline incubations with either linolenic or arachidonic acid acid micelles or liposomes prepared from dilinoleoylphosphatidylcholine. While a 1:1 ratio of Fe2+ and Fe3+ enhanced thiobarbituric acid-reactive product formation in incubations containing linolenic or arachidonic micelles, it reduced the rate of O2 consumption as compared with Fe2+ alone. The results demonstrate that oxidation of Fe2+ in incubations containing lipid substrates is linked to and accelerated by peroxidation of those substrates. Furthermore, the results suggest that oxidation of Fe2+ in the presence of lipid or H2O2 creates forms of iron which differ from those formed during simple Fe2+ autoxidation.
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Affiliation(s)
- J M Braughler
- Central Nervous System Diseases Research Unit, Upjohn Company, Kalamazoo, MI 49001
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64
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Sutton HC, Vile GF, Winterbourn CC. Radical driven Fenton reactions--evidence from paraquat radical studies for production of tetravalent iron in the presence and absence of ethylenediaminetetraacetic acid. Arch Biochem Biophys 1987; 256:462-71. [PMID: 3113335 DOI: 10.1016/0003-9861(87)90603-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Micromolar concentrations of nonchelated ferrous sulfate catalyze a reaction between H2O2 and radiolytically generated paraquat radicals, causing the concurrent oxidation of deoxyribose to thiobarbituric acid reactive products. The oxidation yield per paraquat radical increases with increasing concentration of deoxyribose, and decreases as the instantaneous or steady-state concentration of paraquat radicals is increased, thus explaining previous anomalies in which oxidation was not observed at high paraquat radical concentrations. The process is not mediated by OH. (which gives different products) but is attributed to an oxidizing intermediate resulting from the two electron oxidation of Fe2+ to a peroxo complex, or a derivative of tetravalent iron. Similar but less pronounced concentration dependences occur in the corresponding oxidation of formate or of deoxyribose catalyzed by Fe(EDTA), where at pH 7.3 90% of the pathway is attributed to one electron oxidation of the Fe2+(EDTA) by H2O2, producing OH., while two electron oxidation accounts for the remaining 10%.
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65
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Fatur DJ, San RHC, Davison AJ, Stich HF. CHEMILUMINESCENCE IN THE OXIDATION OF 6-HYDROXYDOPAMINE: EFFECTS OF LUCIGENIN, SCAVENGERS OF ACTIVE OXYGEN, METAL CHELATORS AND THE PRESENCE OF OXYGEN. Photochem Photobiol 1987. [DOI: 10.1111/j.1751-1097.1987.tb05395.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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66
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Aronovitch J, Godinger D, Samuni A, Czapski G. Ascorbic acid oxidation and DNA scission catalyzed by iron and copper chelates. FREE RADICAL RESEARCH COMMUNICATIONS 1987; 2:241-58. [PMID: 2462529 DOI: 10.3109/10715768709065289] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The asorbic acid (AH-) auto-oxidation rates catalyzed by copper chelates of 1,10-phenanthroline (OP) or by iron chelates of bleomycin (BLM) are only slightly higher than the oxidation rates catalyzed by the metal ions. AH- oxidation in the presence of DNA is accompanied by degradation of the DNA. The rates of DNA scission by the metal chelates are markedly higher than the rates induced by the free metal ions. AH- oxidation is slowed down in the presence of DNA which forms ternary complexes with the chelates. The ternary complexes react slowly with AH- but induce DNA double strand breaks more efficiently than the free metal chelates. With OP, DNA is degraded by the reaction of the ternary complex, DNA-(OP)2Cu(I), with H2O2. AH- oxidation in the presence of DNA was biphasic, showing a marked rate increase after DNA was cleaved. We suggest that this sigmoidal pattern of the oxidation curves reflects the low initial oxidative activity of the ternary complexes, accelerating as DNA is degraded. Using O2- produced by pulse radiolysis as a reductant, we found that AH- oxidation with (OP)2Cu(II) induced more DNA double strand breaks per single strand break than bipyridine-copper. The site specific DNA damaging reactions indicated by these results are relevant to the mechanism of cytotoxic activities of bleomycin and similar antibiotics or cytotoxic agents.
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Affiliation(s)
- J Aronovitch
- Department of Molecular Biology, School of Medicine, Hebrew University Jerusalem, Israel
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67
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Rush JD, Koppenol WH. Oxidizing intermediates in the reaction of ferrous EDTA with hydrogen peroxide. Reactions with organic molecules and ferrocytochrome c. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)62677-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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68
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Goldstein S, Czapski G. The role and mechanism of metal ions and their complexes in enhancing damage in biological systems or in protecting these systems from the toxicity of O2-. JOURNAL OF FREE RADICALS IN BIOLOGY & MEDICINE 1986; 2:3-11. [PMID: 3021840 DOI: 10.1016/0748-5514(86)90117-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Copper complexes of 1,10-phenanthroline and some substituted 1,10-phenanthroline cleave DNA in the presence of a reducing agent and molecular oxygen. Generally, the damage is attributed to hydroxyl radicals which are formed through the Haber-Weiss reaction. It is assumed that this reaction occurs with the ternary metal complexes with the biological target and the mechanism is defined as the "site specific mechanism." In these systems, O2- drives the cycle through the reduction of copper(II). On the other hand, these same copper complexes catalyze the dismutation of O2- and thus should protect the systems from O2- toxicity. In this article, the toxicity of these complexes is explained on kinetic grounds. A general discussion on the various factors which could cause the metal ions or their complexes to act either as protectors from O2- toxicity or as sensitizers of toxic effects of O2- is given.
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