scholarly journals Generation of hydrogen peroxide, superoxide and hydroxyl radicals during the oxidation of dihydroxyfumaric acid by peroxidase

1977 ◽  
Vol 163 (3) ◽  
pp. 441-448 ◽  
Author(s):  
B Halliwell
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Hydroxyl Radicals ◽  
Coumaric Acid ◽  
Enzymic Oxidation ◽  
Enzymic Reaction ◽  
Low Rate

1. Dihydroxyfumarate slowly autoxidizes at pH6. This reaction is inhibited by superoxide dismutase but not by EDTA. Mn2+ catalyses dihydroxyfumarate oxidation by reacting with O2 leads to to form Mn3+, which seems to oxidize dihydrofumarate rapidly. Cu2+ also catalyses dihydroxyfumarate oxidation, but by a mechanism that does not involve O2 leads to. 2. Peroxidase catalyses oxidation of dihydroxyfumarate at pH6; addition of H2O2 does not increase the rate. Experiments with superoxide dismutase and catalase suggest that there are two types of oxidation taking place: an enzymic, H2O2-dependent oxidation of dihydroxyfumarate by peroxidase, and a non-enzymic reaction involving oxidation of dihydroxyfumarate by O2 leads to. The latter accounts for most of the observed oxidation of dihydroxyfumarate. 3. During dihydroxyfumarate oxidation, most peroxidase is present as compound III, and the enzymic oxidation may be limited by the low rate of breakdown of this compound. 4. Addition of p-coumaric acid to the peroxidase/dihydroxyfumarate system increases the rate of dihydroxyfumarate oxidation, which is now stimulated by addition of H2O2, and is more sensitive to inhibition by catalase but less sensitive to superoxide dismutase. Compound III is decomposed in the presence of p-coumaric acid. p-Hydroxybenzoate has similar, but much smaller, effects on dihydroxyfumarate oxidation. However, salicylate affects neither the rate nor the mechanism of dihydroxyfumarate oxidation. 5. p-Hydroxybenzoate, salicylate and p-coumarate are hydroxylated by the peroxidase/dihydroxyfumarate system. Experiments using scavengers of hydroxyl radicals shown that OH is required. Ability to increase dihydroxyfumarate oxidation is not necessary for hydroxylation to occur.

scholarly journals Superoxide dismutase enhances the formation of hydroxyl radicals in the reaction of 3-hydroxyanthranilic acid with molecular oxygen

1988 ◽  
Vol 251 (3) ◽  
pp. 893-899 ◽  
Author(s):  
H Iwahashi ◽  
T Ishii ◽  
R Sugata ◽  
R Kido
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Hydroxyl Radical ◽  
Molecular Oxygen ◽  
Hydroxyl Radicals ◽  
Fenton Reaction ◽  
Potassium Phosphate ◽  
Radical Formation ◽  
Superoxide Anions ◽  
Hydroxyanthranilic Acid

Superoxide dismutase (SOD) enhanced the formation of hydroxyl radicals, which were detected by using the e.s.r. spin-trapping technique, in a reaction mixture containing 3-hydroxyanthranilic acid (or p-aminophenol), Fe3+ ions, EDTA and potassium phosphate buffer, pH 7.4. The hydroxyl-radical formation enhanced by SOD was inhibited by catalase and desferrioxamine, and stimulated by EDTA and diethylenetriaminepenta-acetic acid, suggesting that both hydrogen peroxide and iron ions participate in the reaction. The hydroxyl-radical formation enhanced by SOD may be considered to proceed via the following steps. First, 3-hydroxyanthranilic acid is spontaneously auto-oxidized in a process that requires molecular oxygen and yields superoxide anions and anthranilyl radicals. This reaction seems to be reversible. Secondly, the superoxide anions formed in the first step are dismuted by SOD to generate hydrogen peroxide and molecular oxygen, and hence the equilibrium in the first step is displaced in favour of the formation of superoxide anions. Thirdly, hydroxyl radicals are generated from hydrogen peroxide through the Fenton reaction. In this Fenton reaction Fe2+ ions are available since Fe3+ ions are readily reduced by 3-hydroxyanthranilic acid. The superoxide anions do not seem to participate in the reduction of Fe3+ ions, since superoxide anions are rapidly dismuted by SOD present in the reaction mixture.

Improving the growth response ofBorreliaspecies

1995 ◽  
Vol 41 (11) ◽  
pp. 1031-1034 ◽  
Author(s):  
Penelope J. Padgett ◽  
Mary J. Golden ◽  
David J. Pekala
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Hydroxyl Radicals ◽  
Growth Response ◽  
Sodium Formate ◽  
Growth Media ◽  
Aerobic Growth ◽  
Anaerobic Conditions ◽  
Biphasic Medium ◽  
Effective Compound

Borrelia species are microaerophilic spirochetes, i.e., they are unable to grow in the presence of atomospheric oxygen (21%) or under anaerobic conditions. Compounds that have been shown to quench toxic products of oxygen (i.e., superoxide radicals, hydrogen peroxide, hydroxyl radicals, and singlet oxygen) were added to Borrelia growth media (Kelly's medium). Among the compounds tested were catalase, superoxide dismutase, peroxidase, dithiothreitol (DTT), formate, fumarate, dimethyl sulfoxide (DMSO), manganese, activated charcoal (Norit A), mannitol, and a combination of ferric chloride and potassium (meta)bisulfite (iron-bisulfite). Of these, the compounds that were the most effective in enhancing the growth of the species of Borrelia tested were iron-bisulfite, DTT, and DMSO. DTT possesses the ability to break down hydrogen peroxide, and iron-bisulfite has been reported to have superoxide dismutase-like activity in artificial media. Iron-bisulfite, DMSO, sodium formate, DTT, and combinations of these compounds have been incorporated into solid and biphasic Kelley's medium to determine their effect on microaerobic and aerobic growth on plates and in biphasic medium. Iron-bisulfite was the most effective compound tested under these conditions.Key words: Borrelia, bisulfite, spirochetes, microaerobe.

scholarly journals Hydroxylation of p-coumaric acid by horseradish peroxidase. The role of superoxide and hydroxyl radicals

1976 ◽  
Vol 153 (3) ◽  
pp. 513-518 ◽  
Author(s):  
B Halliwell ◽  
S Ahluwalia
Keyword(s):  
Superoxide Dismutase ◽  
Horseradish Peroxidase ◽  
Caffeic Acid ◽  
Hydroxyl Radicals ◽  
Superoxide Radical ◽  
Coumaric Acid ◽  
Low Concentrations ◽  
Superoxide Dismutase 3 ◽  
Superoxide Dismutase 2

1. In the presence of dihydroxyfumarate, horseradish peroxidase catalyses the conversion of p-coumaric acid into caffeic acid at pH 6. This hydroxylation is completely inhibited by superoxide dismutase. 2. Dihydroxyfumarate cannot be replaced by ascorbate H2O2, NADH, cysteine or sulphite. Peroxidase can be replaced by high (10 mM) concentrations of FeSO4, but this reaction is almost unaffected by superoxide dismutase. 3. Hydroxylation by the peroxidase/dihydroxyfumarate system is completely inhibited by low concentrations of Mn2+ or Cu2+. It is proposed that this is due to the ability of these metal ions to react with the superoxide radical O2–. 4. Hydroxylation is partially inhibited by mannitol, Tris or ethanol and completely inhibited by formate. This seems to be due to the ability of these reagents to react with the hydroxyl radical -OH. 5. It is concluded that O2– is generated during the oxidation of dihydroxyfumarate by peroxidase and reacts with H2O2 to produce hydroxyl radicals, which then convert p-coumaric acid into caffeic acid.

Effect of Val 73 → Trp Mutation on the Reaction of “Cambialistic” Superoxide Dismutase fromPropionibacterium shermaniiwith Hydrogen Peroxide

1997 ◽  
Vol 345 (1) ◽  
pp. 156-159 ◽  
Author(s):  
R. Gabbianelli ◽  
A. Battistoni ◽  
C. Capo ◽  
F. Polticelli ◽  
G. Rotilio ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase

scholarly journals Cromoglycate and nedocromil enhanced the reactive oxygen species-dependent suppressions with, but not without, dexamethasone in ischaemic and histamine paw oedema of mice

1997 ◽  
Vol 6 (5-6) ◽  
pp. 369-374
Author(s):  
Y. Oyanagui
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Glucocorticoid Receptor ◽  
Low Dose ◽  
Natural Antioxidant ◽  
Target Cells ◽  
Oxygen Species ◽  
Paw Oedema ◽  
Β Carotene

Anti-inflammatory actions of two anti-allergic drugs, alone or with dexamethasone (Dex) were examined in two models, because inflammation is claimed to be important for allergic events, especially for asthma. Cromoglycate and nedocromil were tested in ischaemic- and histamineinduced paw oedema models of mice. These antiallergic drugs (1–100 mg/kg, i.p.) failed to suppress these oedemata, but enhanced the suppressions by a low dose of dexamethasone (0.1 mg/kg, s.c.) at 3–8 h after Dex injection. The mode of effects by anti-allergic drugs resembled that of a natural antioxidant (α-tocopherol, β-carotene etc.), and was different from that of an immunosuppressant like FK506. The enhancing potencies of the two anti-allergic drugs were similar at 6 h after Dex in both oedemata, and were diminished by superoxide dismutase (SOD) or catalase (i.p.). Cycloheximide completely abolished suppressions. Nedocromil, but not cromoglycate, inhibits inflammatory events. Therefore, there are common unknown actions by which the two anti-allergics enhance suppression by Dex. A possible mechanism of this action was supposed to enhance the superoxide and/or hydrogen peroxide-dependent glucocorticoid receptor (GR) signalling in the target cells.

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