Product Analysis of GG-Specific Photooxidation of DNA via Electron Transfer:  2-Aminoimidazolone as a Major Guanine Oxidation Product

1998 ◽  
Vol 120 (29) ◽  
pp. 7373-7374 ◽  
Author(s):  
Katsuhito Kino ◽  
Isao Saito ◽  
Hiroshi Sugiyama
Keyword(s):  
Electron Transfer ◽  
Oxidation Product ◽  
Product Analysis ◽  
Guanine Oxidation

scholarly journals Amperometric Biosensors Based on Direct Electron Transfer Enzymes

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4525
Author(s):  
Franziska Schachinger ◽  
Hucheng Chang ◽  
Stefan Scheiblbrandner ◽  
Roland Ludwig
Keyword(s):  
Electron Transfer ◽  
Electrode Materials ◽  
Direct Electron Transfer ◽  
Accurate Determination ◽  
Direct Electrochemistry ◽  
Product Analysis ◽  
Amperometric Biosensors ◽  
Chemical Surface ◽  
Fusion Enzymes ◽  
Cost Efficient

The accurate determination of analyte concentrations with selective, fast, and robust methods is the key for process control, product analysis, environmental compliance, and medical applications. Enzyme-based biosensors meet these requirements to a high degree and can be operated with simple, cost efficient, and easy to use devices. This review focuses on enzymes capable of direct electron transfer (DET) to electrodes and also the electrode materials which can enable or enhance the DET type bioelectrocatalysis. It presents amperometric biosensors for the quantification of important medical, technical, and environmental analytes and it carves out the requirements for enzymes and electrode materials in DET-based third generation biosensors. This review critically surveys enzymes and biosensors for which DET has been reported. Single- or multi-cofactor enzymes featuring copper centers, hemes, FAD, FMN, or PQQ as prosthetic groups as well as fusion enzymes are presented. Nanomaterials, nanostructured electrodes, chemical surface modifications, and protein immobilization strategies are reviewed for their ability to support direct electrochemistry of enzymes. The combination of both biosensor elements—enzymes and electrodes—is evaluated by comparison of substrate specificity, current density, sensitivity, and the range of detection.

scholarly journals Photoredox Reaction of trans-4-Stilbenecarboxylatopentaamminecobalt(III)

1979 ◽  
Vol 34 (2) ◽  
pp. 271-274 ◽  
Author(s):  
Arnd Vogler ◽  
Alfred Kern
Keyword(s):  
Electron Transfer ◽  
Chemical Reaction ◽  
Oxidation Product ◽  
Redox Reaction ◽  
Excited Singlet ◽  
Low Complex

AbstractThe irradiation (λ = 313 nm) of aqueous [Co(III)(NH3)5TSC]2+(TSC-= trans-4-stilbenecarboxylate) leads to a redox reaction with formation of Co2+ as has been shown previously. The TSC-ligand is oxidized to the radical in the primary photoreaction. At higher complex concentrations (～10-2 M) this TSC radical is oxidized to stable products (Φ = 0.09 ± 0.02) by [Co(NH3)5TSC]2+,which is reduced to Co2+ leading to release of the TSC- ligand (Φ = 0.07 ± 0.02). Co2+ is thus formed by both the secondary and the primary photo chemical reaction (Φ overall = 0.16). At low complex concentrations (< 10-4 M) in the presence of air, the primary TSC radical is scavenged by O2. Benz-aldehyde is an oxidation product. This reduces the formation of Co2+ to Φ = 0.09 ± 0.02, which is taken to be the efficiency of the primary photo chemical step. It is suggested that the photoredox reaction is initiated by an electron transfer from the first excited singlet of the TSC- ligand. As shown by sensitization experiments, the population of the lowest TSC-triplet leads to the usual trans/cis isomerization of the TSC-ligand, but not to the redox reaction.

Drastic promotion of guanine oxidation via electron transfer in Ψ-type DNA

2019 ◽  
Vol 55 (53) ◽  
pp. 7695-7698 ◽  
Author(s):  
Shunsuke Sakurai ◽  
Mayu Esumi ◽  
Makiko Tanaka
Keyword(s):  
Electron Transfer ◽  
Guanine Oxidation ◽  
Crowded Environment

Drastic promotion of guanine oxidation was induced by not only intraduplex ET but also interduplex ET in Ψ-type DNA in a crowded environment using PEG.

Electrodeposition of guanine oxidation product onto zinc oxide nanoparticles: Application to nanomolar detection of l-cysteine

2009 ◽  
Vol 135 (2) ◽  
pp. 632-641 ◽  
Author(s):  
Rahman Hallaj ◽  
Abdollah Salimi ◽  
Keivan Akhtari ◽  
Saied Soltanian ◽  
Hussein Mamkhezri
Keyword(s):  
Zinc Oxide ◽  
Oxidation Product ◽  
Zinc Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Guanine Oxidation ◽  
Nanomolar Detection

The carbonate radical as one-electron oxidant of carbohydrates in alkaline media

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 143-146
Author(s):  
Magnus Carlsson ◽  
David Stenman ◽  
Gábor Merényi ◽  
Torbjörn Reitberger
Keyword(s):  
Electron Transfer ◽  
Formic Acid ◽  
Gluconic Acid ◽  
Radical Anion ◽  
Alkaline Media ◽  
Product Analysis ◽  
Reaction Sequence ◽  
Carbonate Radical ◽  
Carbonate Radical Anion ◽  
Reaction Schemes

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.

scholarly journals Thrombin-Binding Aptamer Quadruplex Formation: AFM and Voltammetric Characterization

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Victor Constantin Diculescu ◽  
Ana-Maria Chiorcea-Paquim ◽  
Ramon Eritja ◽  
Ana Maria Oliveira-Brett
Keyword(s):  
Electron Transfer ◽  
Surface Coverage ◽  
Pyrolytic Graphite ◽  
Oxidation Potential ◽  
Oxidation Peak ◽  
No Adsorption ◽  
Guanine Oxidation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Quadruplex Formation

The adsorption and the redox behaviour of thrombin-binding aptamer (TBA) and extended TBA (eTBA) were studied using atomic force microscopy and voltammetry at highly oriented pyrolytic graphite and glassy carbon. The different adsorption patterns and degree of surface coverage were correlated with the sequence base composition, presence/absence of K+, and voltammetric behaviour of TBA and eTBA. In the presence of K+, only a few single-stranded sequences present adsorption, while the majority of the molecules forms stable and rigid quadruplexes with no adsorption. Both TBA and eTBA are oxidized and the only anodic peak corresponds to guanine oxidation. Upon addition of K+ions, TBA and eTBA fold into a quadruplex, causing the decrease of guanine oxidation peak and occurrence of a new peak at a higher potential due to the oxidation of G-quartets. The higher oxidation potential of G-quartets is due to the greater difficulty of electron transfer from the inside of the quadruplex to the electrode surface than electron transfer from the more flexible single strands.

Inhibiting guanine oxidation and enhancing the excess-electron-transfer efficiency of a pyrene-modified oligonucleotide by introducing an electron-donating group on pyrene

2019 ◽  
Vol 55 (93) ◽  
pp. 14062-14065 ◽  
Author(s):  
Takumi Okuda ◽  
Yusuke Kawashima ◽  
Yuuya Kasahara ◽  
Tatsuya Takagi ◽  
Junpei Yamamoto ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excess Electron ◽  
Transfer Efficiency ◽  
Guanine Oxidation ◽  
Mediated Electron Transfer ◽  
Reduction Efficiency ◽  
Modified Oligonucleotide

PipPyU and OMePyU enhance the reduction efficiency without oxidizing guanine in DNA-mediated electron transfer.

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