Degradation and transformation of bisphenol A in UV/Sodium percarbonate: Dual role of carbonate radical anion

2020 ◽  
Vol 171 ◽  
pp. 115394 ◽  
Author(s):  
Jiong Gao ◽  
Xiaodi Duan ◽  
Kevin O’Shea ◽  
Dionysios D. Dionysiou
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 ◽  
...  

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.


Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 130-136 ◽  
Author(s):  
Magnus Carlsson ◽  
Johan Lind ◽  
Gábor Merényi

Abstract In the presence of oxygen, radiolytically generated carbonate radical anions, CO3 •–, were reacted with methyl β-D-cellobioside and methyl β-D-glucoside. From the ensuing product pattern, it was concluded that CO3 •– abstracts hydrogen atoms predominantly from glucosidic C1–H bonds. This high intramolecular selectivity was rationalised mainly in terms of a polar effect on the transition state of the hydrogen abstraction reaction. The present findings are in sharp contrast to the relative inertness of CO3 •– towards glucosidic C1–H bonds previously observed in cotton linters. The reasons for this discrepancy are discussed in light of a possible future role of CO3 •– as a bleaching agent for pulp.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 961
Author(s):  
Antonio Francioso ◽  
Alessia Baseggio Conrado ◽  
Carla Blarzino ◽  
Cesira Foppoli ◽  
Elita Montanari ◽  
...  

The β-amyloid (Aβ) peptide plays a key role in the pathogenesis of Alzheimer’s disease. The methionine (Met) residue at position 35 in Aβ C-terminal domain is critical for neurotoxicity, aggregation, and free radical formation initiated by the peptide. The role of Met in modulating toxicological properties of Aβ most likely involves an oxidative event at the sulfur atom. We therefore investigated the one- or two-electron oxidation of the Met residue of Aβ25-35 fragment and the effect of such oxidation on the behavior of the peptide. Bicarbonate promotes two-electron oxidations mediated by hydrogen peroxide after generation of peroxymonocarbonate (HCO4−, PMC). The bicarbonate/carbon dioxide pair stimulates one-electron oxidations mediated by carbonate radical anion (CO3•−). PMC efficiently oxidizes thioether sulfur of the Met residue to sulfoxide. Interestingly, such oxidation hampers the tendency of Aβ to aggregate. Conversely, CO3•− causes the one-electron oxidation of methionine residue to sulfur radical cation (MetS•+). The formation of this transient reactive intermediate during Aβ oxidation may play an important role in the process underlying amyloid neurotoxicity and free radical generation.


2009 ◽  
Vol 35 (4) ◽  
pp. 401-409 ◽  
Author(s):  
L. Gebicka ◽  
J. Didik ◽  
J. L. Gebicki

2020 ◽  
Vol 56 (68) ◽  
pp. 9779-9782 ◽  
Author(s):  
Aaron M. Fleming ◽  
Cynthia J. Burrows

Fe(ii)-Fenton reaction in bicarbonate buffer yields CO3˙−, not HO˙, oxidizing 2′-deoxyguanosine to yield 8-oxo-7,8-dihydro-2′-deoxyguanosine with no ribose damage.


Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 143-146
Author(s):  
Magnus Carlsson ◽  
David Stenman ◽  
Gábor Merényi ◽  
Torbjörn Reitberger

Abstract The mechanism by which the carbonate radical anion reacts with D-glucose in alkaline aqueous solutions has been studied by means of γ-radiolysis. From the product analysis it is concluded that the reaction sequence is initiated by a one-electron transfer between the carbonate radical anion and deprotonated D-glucose. In the presence of molecular oxygen, the major, if not only products of this reaction sequence are formic acid, arabinose and gluconic acid and reaction schemes are proposed to account for the observed formation of these products.


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