Structural Tuning of Multishelled Hollow Microspheres for Boosted Peroxymonosulfate Activation and Selectivity: Role of Surface Superoxide Radical

2021 ◽  
pp. 121019
Author(s):  
Wenqian Li ◽  
Xu He ◽  
Boda Li ◽  
Bin Zhang ◽  
Ting Liu ◽  
...  
Keyword(s):  
Superoxide Radical ◽  
Hollow Microspheres

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

scholarly journals Reactivity of Superoxide Radical Anion with Cyclic Nitrones:  Role of Intramolecular H-Bond and Electrostatic Effects

2007 ◽  
Vol 129 (26) ◽  
pp. 8177-8191 ◽  
Author(s):  
Frederick A. Villamena ◽  
Shijing Xia ◽  
John K. Merle ◽  
Robert Lauricella ◽  
Beatrice Tuccio ◽  
...  
Keyword(s):  
Radical Anion ◽  
Superoxide Radical ◽  
Electrostatic Effects ◽  
Superoxide Radical Anion ◽  
Cyclic Nitrones

Protection against Superoxide and Hydrogen Peroxide in Synovial Fluid from Rheumatoid Patients

1981 ◽  
Vol 61 (4) ◽  
pp. 483-486 ◽  
Author(s):  
D. R. Blake ◽  
N. D. Hall ◽  
D. A. Treby ◽  
B. Halliwell ◽  
J. M. C. Gutteridge
Keyword(s):  
Hydrogen Peroxide ◽  
Synovial Fluid ◽  
Oxygen Radicals ◽  
Superoxide Radical ◽  
Joint Disease ◽  
Polymorphonuclear Leucocytes ◽  
Inflammatory Joint Disease ◽  
Normal Range ◽  
Lubricating Properties

1. On exposure of synovial fluid to superoxide and hydrogen peroxide, generated enzymically or by activated polymorphonuclear leucocytes, hyaluronic acid is depolymerized and the fluid loses its lubricating properties. The ability of synovial fluid from rheumatoid patients to scavenge superoxide and hydrogen peroxide was therefore examined. 2. Synovial fluid from a range of rheumatoid patients contained no superoxide dismutase activity, insufficient caeruloplasmin to scavenge any superoxide radical and little, if any, catalase activity. 3. Total ascorbate (reduced ascorbate + dehydroascorbate) concentrations in the plasma and synovial fluid of rheumatoid patients were similar in each case. The values are at the low end of the normal range. 4. These results are discussed in relation to the role of oxygen radicals in inflammatory joint disease.

scholarly journals Regulation of superoxide generation by myeloperoxidase during the respiratory burst of human neutrophils

1986 ◽  
Vol 237 (2) ◽  
pp. 601-604 ◽  
Author(s):  
S W Edwards ◽  
T F Swan
Keyword(s):  
Respiratory Burst ◽  
Cytochalasin B ◽  
Superoxide Radical ◽  
Human Neutrophils ◽  
Second Phase ◽  
Chemotactic Peptide ◽  
O2 Uptake ◽  
Superoxide Generation ◽  
Lower Magnitude

The role of myeloperoxidase in the regulation of the respiratory burst of human neutrophils activated by the chemotactic peptide (N-formyl-L-methionyl-L-leucyl-L-phenylalanine) plus cytochalasin B was determined by using anti-(human myeloperoxidase) antibody. The respiratory burst activated under these conditions consisted of an initial (1-2 min) phase with high rates of O2 uptake, luminol-dependent chemiluminescence and superoxide radical (O2-.) generation and a second, more sustained, phase of lower magnitude of chemiluminescence and O2 uptake: O2-. generation did not occur during this second phase. In cell suspensions stimulated in the presence of anti-(human myeloperoxidase) antibody, the magnitude of the initial phase of both O2 uptake and O2-. generation was unaffected, but these high rates were maintained over much longer periods than in control suspensions. It is therefore proposed that a product of myeloperoxidase normally regulates the duration of O2-. generation during the respiratory burst, possibly by inhibition of NADPH oxidase.

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.

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