Studies on the reactions of ferric iron with glutathione and some related thiols. Part III. A study of the iron catalyzed oxidation of glutathione by molecular oxygen

Hamed, Mazen Y.; Silver, Jack; Wilson, Michael T.

doi:10.1016/s0020-1693(00)91289-1

Cited by 39 publications

(22 citation statements)

References 24 publications

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“…On the basis of these results obtained in model wine (Figure 4B) and in comparison to previous studies where GSH and Cys were shown to reduce Fe(III) in simple aqueous systems, 15,16 it is apparent that tartaric acid inhibits both the coordination of thiols with Fe(III) and its subsequent reduction to Fe(II). Furthermore, because Fe(III) coordinates preferentially with carboxylate moieties rather than with the thiolate function at wine pH, 16 it would appear that Fe(III) remains bound to tartaric acid. However, as a result of its carboxylate function, Cys can presumably compete for Fe to displace tartrate ligands.…”

Section: ■ Results and Discussionsupporting

confidence: 82%

“…Studies performed with glutathione (GSH) in a pH range (3–7) have shown that Fe(II) is spontaneously produced when GSH is added to Fe(III) (Figure ). , The same has been shown with Cys at low pH, because the Fe(III)–Cys complex is unstable and quickly reacts to yield Fe(II) and cystine . Previous work has failed to provide evidence of free thiyl radical generation under those conditions, and disulfide is seemingly formed in situ before being released from the metal complex.…”

Section: Introductionmentioning

confidence: 70%

“…It was concluded that coordination to GSSG, GSH, and also Cys occurred by interaction with carboxylate groups under acidic conditions (pH < 4). 15,16 As discussed above, Fe(II) produced can be reoxidized to Fe(III) by reacting with O 2 , with the reaction markedly accelerated by copper.…”

Section: ■ Introductionmentioning

confidence: 98%

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Reaction Mechanisms of Metals with Hydrogen Sulfide and Thiols in Model Wine. Part 2: Iron- and Copper-Catalyzed Oxidation

Kreitman

Danilewicz²,

Jeffery

et al. 2016

J. Agric. Food Chem.

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Sulfidic off-odors arising during wine production are frequently removed by Cu(II) fining. In part 1 of this study ( 10.1021/acs.jafc.6b00641 ), the reaction of H2S and thiols with Cu(II) was examined; however, the interaction of iron and copper is also known to play an important synergistic role in mediating non-enzymatic wine oxidation. The interaction of these two metals in the oxidation of H2S and thiols (cysteine, 3-sulfanylhexan-1-ol, and 6-sulfanylhexan-1-ol) was therefore examined under wine-like conditions. H2S and thiols (300 μM) were reacted with Fe(III) (100 or 200 μM) alone and in combination with Cu(II) (25 or 50 μM), and concentrations of H2S and thiols, oxygen, and acetaldehyde were monitored over time. H2S and thiols were shown to be slowly oxidized in the presence of Fe(III) alone and were not bound to Fe(III) under model wine conditions. However, Cu(II) added to model wine containing Fe(III) was quickly reduced by H2S and thiols to form Cu(I) complexes, which then rapidly reduced Fe(III) to Fe(II). Oxidation of Fe(II) in the presence of oxygen regenerated Fe(III) and completed the iron redox cycle. In addition, sulfur-derived oxidation products were observed, and the formation of organic polysulfanes was demonstrated.

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Section: ■ Results and Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 70%

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Reaction Mechanisms of Metals with Hydrogen Sulfide and Thiols in Model Wine. Part 2: Iron- and Copper-Catalyzed Oxidation

Kreitman

Danilewicz²,

Jeffery

et al. 2016

J. Agric. Food Chem.

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“…We monitored peroxynitrite decomposition in a deoxygenated buffer (100 mM phosphate buffer) in the absence and presence of GSH alone or iron(II)/glutathione (GSH) mixtures using UV-visible spectroscopy to test this hypothesis. GSH and ferrous iron form a 2:1 stoichiometry complex, which is a likely cellular LIP complex (37)(38)(39). The decomposition of peroxynitrite in buffer alone followed firstorder kinetics, with a rate constant of 0.19 Ϯ 0.1 s Ϫ1 , a value that is close to the value expected using these experimental conditions (15,40).…”

Section: Iron(ii)-gsh Complexes React With Peroxynitritesupporting

confidence: 64%

The labile iron pool attenuates peroxynitrite-dependent damage and can no longer be considered solely a pro-oxidative cellular iron source

Damasceno

Condeles

Lopes

et al. 2018

Journal of Biological Chemistry

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The ubiquitous cellular labile iron pool (LIP) is often associated with the production of the highly reactive hydroxyl radical, which forms through a redox reaction with hydrogen peroxide. Peroxynitrite is a biologically relevant peroxide produced by the recombination of nitric oxide and superoxide. It is a strong oxidant that may be involved in multiple pathological conditions, but whether and how it interacts with the LIP are unclear. Here, using fluorescence spectroscopy, we investigated the interaction between the LIP and peroxynitrite by monitoring peroxynitrite-dependent accumulation of nitrosated and oxidized fluorescent intracellular indicators. We found that, in murine macrophages, removal of the LIP with membrane-permeable iron chelators sustainably accelerates the peroxynitrite-dependent oxidation and nitrosation of these indicators. These observations could not be reproduced in cell-free assays, indicating that the chelator-enhancing effect on peroxynitrite-dependent modifications of the indicators depended on cell constituents, presumably including LIP, that react with these chelators. Moreover, neither free nor ferrous-complexed chelators stimulated intracellular or extracellular oxidative and nitrosative chemistries. On the basis of these results, LIP appears to be a relevant and competitive cellular target of peroxynitrite or its derived oxidants, and thereby it reduces oxidative processes, an observation that may change the conventional notion that the LIP is simply a cellular source of pro-oxidant iron.

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“…Thiols should be considered as transition metal ligands in thiol-mediated LPO (19). Based on stop-flow kinetics and Mossbauer spectra, a complex of (Fe2+-GSH)202 has been suggested as the reactive species in the Fecatalyzed oxidation of GSH (20). Similarly, Cu-thiol complexes have been shown to exist, where facile redox reactions of thiols and Cu occur (21).…”

Section: Vol 40 No 6 1996mentioning

confidence: 99%

The role of chelators in the catalysis of glutathione‐γ‐glutamyl transpeptidase‐dependent lipid peroxidation by transition metals

1996

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A T-glutamyl transpeptidase-glutathione (GGT-GSH) system induces transition metaldependent lipid peroxidation (LPO). The role of the transition metals iron and copper in this system was studied by determination of LPO rates, the rates of Fe 3+ reduction, and the steady state concentration of Fe 2÷ as function of concentration of o-phenanthroline or citrate. Optimum curves were obtained,compatible with the idea that Fe 2+ chelated by an entity other than o-phenanthroline or citrate is important in thioi-driven LPO. Cu enhanced LPO at low concentrations, inhibited LPO at high ones, and catalytically elevated the steady state concentration of Fe 2+. Relating the steady states of Fe 2+ at various chelator concentrations with those of LPO rates, indicate that a Fe2÷-O-O-Fe3+ complex may not be the principal oxidizing entity. The above, and the resistance of LPO to catalase, superoxide dismutase and mannitol are compatible with the notion that the Fe which participates in redox cycles is chelated to an entity that may be refractory to the action of these antioxidants. BIOCHEMISTRY and MOLECULAR BIOLOGY INTERNATIONALGSH-GGT-mediated LPO rates in rat liver microsomes, and the levels of the reduction of Fe 3÷, indicate that a complex other than Fe 2+-O-O-Fe a+ (perhaps thiol-Fe) complex is important for the induction of LPO by thiols, and that Cu enhances LPO by increasing the steady state of ferrous iron.MATERIALS AND METHODS Materials. Glutathione (GSH), dithiothreitol (DTY), glycylglycine, thiobarbituric acid (TBA), acivicin, butylated hydroxyanisol (BHA), catarase (CAT, 11,000 U/mg) and superoxide dismutase (SOD, 2,670 U/rag) were from Sigma, Saint Louis. o-phenanthroline (OP) was from Aldrich, Milwaukee. Malondialdehyde-bis-dimethylacetal was from Eastman-Kodak, Rochester. Cysteinyl-bisglycine was from Bachem, Torrance, CA. Rat liver and kidney microsomes were prepared from Wistar rats weighing 250 g. Organs were homogenized in 5 ml/g tissue of ice cold 50 mM sodium phosphate, 150 mM NaC! buffer pH 7.4 and were centrifuged at 9,000 x g for 20 min. The upper lipid layer was removed with filter paper, and the supernatant was centrifuged at 43,000 x g for 30 min, and the pellets (microsomes) were washed twice and resuspended in the same buffer, aliquoted, frozen and stored at -80°C. GGT activity was assayed with 1 ram L-3,-glutamyl-p-nitroanilide and 20 raM glycylglycine in 50 mM HEPES buffer pH 7.4 at 25°C. GGT activity was not affected by iron, copper, BHA, mannitol, OP, citrate or antioxidant enzymes at the concentrations used here. Protein concentration was determined with the Bradford reagent (Bio-Rad) with bovine serum albumin as a standard. The specific activities of GGT in liver and kidney microsomes were 20 mU and 25 U/rag protein, respectively. Thiobarbiturie acid-reactive material was assayed essentially as described (12) with a TBA-TCA-HC! reagent containing 3 mM BHA. A 500/zl sample of reaction mixture was mixed with 1.5 ml of the TBA-TCA-HCI reagent and was incubated at 85°C for 15 rain, followed by centri...

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Studies on the reactions of ferric iron with glutathione and some related thiols. Part III. A study of the iron catalyzed oxidation of glutathione by molecular oxygen

Cited by 39 publications

References 24 publications

Reaction Mechanisms of Metals with Hydrogen Sulfide and Thiols in Model Wine. Part 2: Iron- and Copper-Catalyzed Oxidation

Reaction Mechanisms of Metals with Hydrogen Sulfide and Thiols in Model Wine. Part 2: Iron- and Copper-Catalyzed Oxidation

The labile iron pool attenuates peroxynitrite-dependent damage and can no longer be considered solely a pro-oxidative cellular iron source

The role of chelators in the catalysis of glutathione‐γ‐glutamyl transpeptidase‐dependent lipid peroxidation by transition metals

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