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.

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

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.

scholarly journals Cu,Zn-superoxide dismutase-driven free radical modifications: copper- and carbonate radical anion-initiated protein radical chemistry

2008 ◽  
Vol 417 (1) ◽  
pp. 341-353 ◽  
Author(s):  
Dario C. Ramirez ◽  
Sandra E. Gomez-Mejiba ◽  
Jean T. Corbett ◽  
Leesa J. Deterding ◽  
Kenneth B. Tomer ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Active Site ◽  
Radical Anion ◽  
Brain Homogenate ◽  
Experimental Conditions ◽  
Carbonate Radical ◽  
Carbonate Radical Anion ◽  
Protein Radicals ◽  
Mouse Brain Homogenate

The understanding of the mechanism, oxidant(s) involved and how and what protein radicals are produced during the reaction of wild-type SOD1 (Cu,Zn-superoxide dismutase) with H2O2 and their fate is incomplete, but a better understanding of the role of this reaction is needed. We have used immuno-spin trapping and MS analysis to study the protein oxidations driven by human (h) and bovine (b) SOD1 when reacting with H2O2 using HSA (human serum albumin) and mBH (mouse brain homogenate) as target models. In order to gain mechanistic information about this reaction, we considered both copper- and CO3•− (carbonate radical anion)-initiated protein oxidation. We chose experimental conditions that clearly separated SOD1-driven oxidation via CO3•− from that initiated by copper released from the SOD1 active site. In the absence of (bi)carbonate, site-specific radical-mediated fragmentation is produced by SOD1 active-site copper. In the presence of (bi)carbonate and DTPA (diethylenetriaminepenta-acetic acid) (to suppress copper chemistry), CO3•− produced distinct radical sites in both SOD1 and HSA, which caused protein aggregation without causing protein fragmentation. The CO3•− produced by the reaction of hSOD1 with H2O2 also produced distinctive DMPO (5,5-dimethylpyrroline-N-oxide) nitrone adduct-positive protein bands in the mBH. Finally, we propose a biochemical mechanism to explain CO3•− production from CO2, enhanced protein radical formation and protection by (bi)carbonate against H2O2-induced fragmentation of the SOD1 active site. Our present study is important for establishing experimental conditions for studying the molecular mechanism and targets of oxidation during the reverse reaction of SOD1 with H2O2; these results are the first step in analysing the critical targets of SOD1-driven oxidation during pathological processes such as neuroinflammation.

scholarly journals Role of superoxide radical anion in the mechanism of apoB100 degradation induced by DHA in hepatic cells

2011 ◽  
Vol 25 (10) ◽  
pp. 3554-3560 ◽  
Author(s):  
Ursula Andreo ◽  
Josh Elkind ◽  
Courtney Blachford ◽  
Arthur I. Cederbaum ◽  
Edward A. Fisher
Keyword(s):  
Radical Anion ◽  
Superoxide Radical ◽  
Superoxide Radical Anion ◽  
Hepatic Cells

The Role of Superoxide Radical Anion in Signal Transduction

2000 ◽  
Vol 28 (5) ◽  
pp. A284-A284
Author(s):  
Moon B. Yim ◽  
William C. Barrett ◽  
Hyoung-Pyo Kim ◽  
P. Boon Chock
Keyword(s):  
Signal Transduction ◽  
Radical Anion ◽  
Superoxide Radical ◽  
Superoxide Radical Anion
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