Colorimetric visualization of superoxide dismutase in serum via etching of Au nanorods from superoxide radical

2018 ◽  
Vol 259 ◽  
pp. 1066-1072 ◽  
Author(s):  
Simin Lu ◽  
Xiao Zhang ◽  
Ling Chen ◽  
Ping Yang
Keyword(s):  
Superoxide Dismutase ◽  
Superoxide Radical ◽  
Au Nanorods ◽  
Colorimetric Visualization

Antioxidant enzymes in intramural nerves of the opossum esophagus

1996 ◽  
Vol 270 (1) ◽  
pp. G136-G142 ◽  
Author(s):  
R. M. Thomas ◽  
S. Fang ◽  
L. S. Leichus ◽  
L. W. Oberley ◽  
J. Christensen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Superoxide Dismutase ◽  
Antioxidant Enzymes ◽  
Superoxide Radical ◽  
Muscularis Propria ◽  
Enteric Neurons ◽  
Enzyme Assays ◽  
Nerve Bundles ◽  
Diethyldithiocarbamic Acid ◽  
Esophageal Muscle

Superoxide radical (O2-.) combines with nitric oxide (NO) to form peroxynitrite, thereby nullifying the biological activity of NO. Superoxide dismutase (SOD) prevents this reaction by converting O2-. to H2O2. We tested the hypotheses that the antioxidant enzymes catalase (CAT), Mn SOD, and Cu/Zn SOD are present in enteric neurons of the opossum esophagus, and that O2-. alters esophageal motor function. Immunostaining demonstrated CAT, Mn SOD, and Cu/Zn SOD immunoreactivity in interganglionic nerve bundles and ganglia of the myenteric and submucosal plexuses. Western blot analysis confirmed the presence of these enzymes in homogenates of esophageal muscularis propria, and enzyme assays demonstrated Cu/Zn SOD and Mn SOD activities of 262 and 73 U/mg protein, respectively. Both diethyldithiocarbamic acid, an inhibitor of Cu/Zn SOD, and xanthine (X) with xanthine oxidase (XO), which generate O2-., shortened the latency of the nerve-mediated contraction of circular esophageal muscle, the off response, by 20.2 and 23.4%, respectively. SOD alone did not affect the latency, but it inhibited the effect of X with XO on the latency. Antioxidant enzymes found in intramural esophageal nerves may play a role in regulating NO-mediated neuromuscular communication in the esophagus.

scholarly journals Superoxide radical induces sclerotial differentiation in filamentous phytopathogenic fungi: a superoxide dismutase mimetics study

Microbiology ◽  
2010 ◽  
Vol 156 (3) ◽  
pp. 960-966 ◽  
Author(s):  
Ioannis Papapostolou ◽  
Christos D. Georgiou
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Superoxide Dismutase ◽  
Sclerotinia Sclerotiorum ◽  
Superoxide Radical ◽  
Sclerotium Rolfsii ◽  
Phytopathogenic Fungi ◽  
Indirect Indicator ◽  
Superoxide Dismutase Mimetics ◽  
Sclerotial Differentiation

This study shows that the superoxide radical (O2 •−), a direct indicator of oxidative stress, is involved in the differentiation of the phytopathogenic filamentous fungi Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium rolfsii and Sclerotinia minor, shown by using superoxide dismutase (SOD) mimetics to decrease their sclerotial differentiation. The production rate of O2 •− and SOD levels in these fungi, as expected, were significantly lowered by the SOD mimetics, with concomitant decrease of the indirect indicator of oxidative stress, lipid peroxidation.

scholarly journals Ascorbic acid, metal ions and the superoxide radical

1976 ◽  
Vol 155 (3) ◽  
pp. 697-700 ◽  
Author(s):  
B Halliwell ◽  
C H Foyer
Keyword(s):  
Ascorbic Acid ◽  
Superoxide Dismutase ◽  
Bovine Serum Albumin ◽  
Metal Ions ◽  
Bovine Serum ◽  
Superoxide Radical ◽  
Alkaline Ph ◽  
Ph Values ◽  
Stimulation Of

1. No evidence could be found for production of the superoxide radical, O2-, during autoxidation of ascorbic acid at alkaline pH values. Indeed, ascorbate may be important in protection against O2- genat-d in vivo. 2. Oxidation of ascorbate at pH 10.2 was stimulated by metal ions. Stimulation by Fe2+ was abolished by superoxide dismutase, probably because of generation of O2- during reduction of O2 by Fe2+, followed by reaction of O2- with ascorbate. EDTA changed the mechanism of Fe2+-stimulated ascorbate oxidation. 3. Stimulation of ascorbate oxidation by Cu2+ was also decreased by superoxide dismutase, but this appears to be an artifact, since apoenzyme or bovine serum albumin showed similar effects.

scholarly journals The rate of reaction of superoxide radical ion with oxyhaemoglobin and methaemoglobin

1976 ◽  
Vol 155 (3) ◽  
pp. 503-510 ◽  
Author(s):  
H C Sutton ◽  
P B Roberts ◽  
C C Winterbourn
Keyword(s):  
Superoxide Dismutase ◽  
Xanthine Oxidase ◽  
Rate Constants ◽  
Superoxide Radical ◽  
Radical Ions ◽  
Catalysed Oxidation ◽  
Rate Of Reaction ◽  
Radiolytic Reduction

Superoxide radical ions (O2-) produced by the radiolytic reduction of oxygenated formate solutions and by the xanthine oxidase-catalysed oxidation of xanthine were shown to oxidize the haem groups in oxyhaemoglobin and reduce those in methaemoglobin as in reactions (1) and (2): (see articles) Reaction (1) is suppressed by reaction (8) when [O2-]exceeds 10 muM, but consumes all the O2- generated in oxyhaemoglobin solutions when [oxyhaemoglobin] greater than 160 muM and [O2-]less than 1 nM at pH 7. The yield of reaction (2) is also maximal in methaemoglobin solutions under similar conditions, but less than one haem group is reduced per O2- radical. From studies of (a) the yield of reactions (1) and (2) at variable [haemoglobin] and rates of production of O2-, (b) their suppression by superoxide dismutase, and (c) equilibria observed with mixtures of oxyhaemoglobin and methaemoglobin, it is shown that k1/k2=0.7 +/- 0.2 and k1 = (4 +/- 1) × 10(3) M-1-S-1 At pH7, and k1 and k2 decrease with increasing pH. Concentrations and rate constants are expressed in terms of haem-group concentrations. Concentrations of superoxide dismutase observed in normal erythrocytes are sufficient to suppress reactions (1) and (2), and hence prevent the formation of excessive methaemoglobin.

Superoxide dismutase protects against paraquat-mediated dioxygen toxicity and mutagenicity: studies in Salmonella typhimurium

1982 ◽  
Vol 60 (11) ◽  
pp. 1367-1373 ◽  
Author(s):  
Hosni M. Hassan ◽  
Carmella S. Moody
Keyword(s):  
Superoxide Dismutase ◽  
Free Radicals ◽  
Salmonella Typhimurium ◽  
Normal Level ◽  
Ames Test ◽  
Superoxide Radical ◽  
Oxygen Free Radicals ◽  
Chromosomal Breaks ◽  
Oxygen Sensitive ◽  
Mutagenic Effects

Paraquat is univalently reduced to the relatively stable, but oxygen-sensitive, paraquat radical (PQ∙+). This PQ∙+ can react with dioxygen to generate the superoxide radical, which can further generate other more deleterious species of oxygen free radicals (i.e., hydroxyl radical, OH∙). These oxygen free radicals are known to cause chromosomal breaks; therefore, it was logical to postulate that paraquat is a mutagen. This proved to be the case when tested in a modified Ames test using a liquid incubation assay. Salmonella typhimurium strains TA98 and TA100 were grown in the presence of various concentrations of PQ, as well as in the presence of known mutagenic compounds: mitomycin C, azide, and proflavine. Paraquat was much more toxic and mutagenic in a simple nutritionally restricted medium than in a rich complex medium and these toxic and mutagenic effects were oxygen dependent. Furthermore, cells containing high levels of superoxide dismutase were more resistant to the toxic and mutagenic effects of paraquat than were cells containing a normal level of this enzyme.

Catalytic role of iron-superoxide dismutase in hydrogen abstraction by super oxide radical anion from ascorbic acid

RSC Advances ◽  
2016 ◽  
Vol 6 (89) ◽  
pp. 86650-86662 ◽  
Author(s):  
Manish K. Tiwari ◽  
Phool C. Mishra
Keyword(s):  
Ascorbic Acid ◽  
Superoxide Dismutase ◽  
Active Site ◽  
Radical Anion ◽  
Superoxide Radical ◽  
Hydrogen Abstraction ◽  
Iron Superoxide Dismutase ◽  
Superoxide Radical Anion ◽  
Catalytic Role

The catalytic role of iron-superoxide dismutase (Fe-SOD) in the working of ascorbic acid (AA) as a superoxide radical anion scavenger has been studied by employing a model developed recently for the active site of the enzyme.

No effect of superoxide dismutase on spontaneous development of diabetes in db/db mice

1988 ◽  
Vol 117 (1) ◽  
pp. 99-102
Author(s):  
Ove Berglund ◽  
Kjell Grankvist ◽  
Carina Albiin ◽  
Stefan L. Marklund
Keyword(s):  
Superoxide Dismutase ◽  
B Cells ◽  
Superoxide Radical ◽  
Superoxide Radicals ◽  
Cuzn Superoxide Dismutase

Abstract. B-cells have previously been shown to be very susceptible to damage induced by superoxide radicals, and protection against such damage has been achieved both in vitro and in vivo with superoxide dismutase. During maturation, db/db mice develop diabetes and accumulation of potentially superoxide radical-producing leucocytes can be demonstrated in the islets during the process. To test for the possibility that superoxide radical-induced damage contributes to the development of diabetes, db/db mice were given daily ip injections of 200 mg/kg polyethylene glycolsubstituted CuZn superoxide dismutase. No effect of the treatment could be demonstrated.

scholarly journals Oxidative denitrification of Nω-hydroxy-l-arginine by the superoxide radical anion

1996 ◽  
Vol 317 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Steven A. EVERETT ◽  
Madeleine F. DENNIS ◽  
Kantilal B. PATEL ◽  
Michael R. L. STRATFORD ◽  
Peter WARDMAN
Keyword(s):  
Nitric Oxide ◽  
Superoxide Dismutase ◽  
Catalytic Activity ◽  
Radical Anion ◽  
Superoxide Radical ◽  
Superoxide Radical Anion ◽  
Prototropic Equilibrium ◽  
Ph Dependent ◽  
Oxide Synthase ◽  
Cytochrome P 450

The superoxide radical anion (O2-•) produced during the catalytic activity of nitric oxide synthase (NOS) and cytochrome P-450 has been implicated in the oxidative denitrification of hydroxyguanidines (> C = NOH). The reactivity of the radiolytically generated O2-• radical with Nω-hydroxy-l-arginine (NHA) is pH dependent and appears to parallel the prototropic equilibrium of the hydroxyguanidino group (> C = NOH ⇌ > C = NO- + H+; pK = 8). The Nω-hydroxyguanidino group is more reactive towards O2-• when deprotonated but exhibits negligible reactivity when protonated. Based on a model, the rate constant for the reaction of the O2-• with NHA was estimated as k (O2-•+ > C = NO-) ≈ 200–500 M-1·s-1, which is probably too low to compete with O2-• reactions with NO• or superoxide dismutase, which occur many orders of magnitude faster. The oxidative elimination of NO from NHA by O2-• was not accompanied by the formation of l-citrulline. Since only 21% of NHA will exist in the deprotonated > C = NO- form at physiological pH, it is unlikely that oxidative denitrification of NHA by cytochrome P-450 or NOS-derived O2-• radicals will prove a major free-radical pathway to NO• and l-citrulline.

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