scholarly journals Electron Transfer of Myoglobin Immobilized in Au Electrodes Modified with a RAFT PMMA-Block-PDMAEMA Polymer

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Carla N. Toledo ◽  
Fábio H. Florenzano ◽  
José M. Schneedorf
Keyword(s):  
Electron Transfer ◽  
Chain Transfer ◽  
Reduction Potential ◽  
Hydrophobic Interactions ◽  
Cyclic Voltammograms ◽  
Redox Center ◽  
Heterogeneous Electron Transfer ◽  
A Value ◽  
Reversible Addition ◽  
Raft Polymers

Myoglobin was immobilized with poly(methyl methacrylate)-block-poly[(2-dimethylamino)ethyl methacrylate]PMMA-block-PDMAEMA polymer synthesized by reversible addition-fragmentation chain transfer technique (RAFT). Cyclic voltammograms gave direct and slow quasireversible heterogeneous electron transfer kinetics between Mb-PMMA-block-PDMAEMA modified electrode and the redox center of the protein. The values for electron rate constant (Ks) and transfer coefficient (α) were0.055±0.01·s−1and0.81±0.08, respectively. The reduction potential determined as a function of temperature (293–328 K) revealed a value of reaction center entropy ofΔS0of351.3±0.0002 J·mol−1·K−1and enthalpy change of-76.8±0.1 kJ·mol−1, suggesting solvent effects and charge ionization atmosphere involved in the reaction parallel to hydrophobic interactions with the copolymer. The immobilized protein also exhibits an electrocatalytical response to reduction of hydrogen peroxide, with an apparentKmof114.7±58.7 μM. The overall results substantiate the design and use of RAFT polymers towards the development of third-generation biosensors.

Organo-photocatalysts for photoinduced electron transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization

2015 ◽  
Vol 6 (31) ◽  
pp. 5615-5624 ◽  
Author(s):  
Jiangtao Xu ◽  
Sivaprakash Shanmugam ◽  
Hien T. Duong ◽  
Cyrille Boyer
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Photoinduced Electron Transfer ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Reversible Addition ◽  
Methacrylate Monomers

In this work, we demonstrate the use of organophotoredox catalysts under visible light to perform photoinduced electron transfer-reversible addition fragmentation chain transfer (PET-RAFT) for the polymerization of methacrylate monomers.

Synthesis of RAFT polymers as bivalent inhibitors of cholera toxin

RSC Advances ◽  
2014 ◽  
Vol 4 (29) ◽  
pp. 14868-14871 ◽  
Author(s):  
David J. Leaver ◽  
Andrew B. Hughes ◽  
Raymond M. Dawson ◽  
Almar Postma ◽  
Nino Malic ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Cholera Toxin ◽  
Chain Transfer ◽  
Low Molecular Weight ◽  
Reversible Addition ◽  
New Strategy ◽  
Bivalent Inhibitors ◽  
Raft Polymers

We report a new strategy to develop low molecular weight (18–28 kDa) poly(N-acryloylmorpholine) (PNAM) polymers as bivalent inhibitors of cholera toxin (CT) using Reversible Addition–Fragmentation chain Transfer (RAFT) technology.

scholarly journals Unmediated heterogeneous electron transfer reaction of ascorbate oxidase and laccase at a gold electrode

1998 ◽  
Vol 332 (3) ◽  
pp. 611-615 ◽  
Author(s):  
Roberto SANTUCCI ◽  
Tommaso FERRI ◽  
Laura MORPURGO ◽  
Isabella SAVINI ◽  
Luciana AVIGLIANO
Keyword(s):  
Electron Transfer ◽  
Electrode Surface ◽  
Gold Electrode ◽  
Ascorbate Oxidase ◽  
Cyclic Voltammograms ◽  
Intramolecular Electron Transfer ◽  
Redox Potentials ◽  
Catalytic Current ◽  
Heterogeneous Electron Transfer

The unmediated electrochemistry of two large Cu-containing proteins, ascorbate oxidase and laccase, was investigated by direct-current cyclic voltammetry. Rapid heterogeneous electron transfer was achieved in the absence of promoters or mediators by trapping a small amount of protein within a solid, electrochemically inert, tributylmethyl phosphonium chloride membrane coating a gold electrode. The problems typical of proteins in solution, such as adsorption on the electrode surface, were avoided by this procedure. In anaerobic conditions, the cyclic voltammograms, run at a scan rate of up to 200 mV/s, showed the electron transfer process to be quasi-reversible and diffusion-controlled. The pH-dependent redox potentials (+360 mV and +400 mV against a normal hydrogen electrode at pH 7.0 for ascorbate oxidase and laccase respectively and +390 mV and +410 mV at pH 5.5) were similar to those of the free proteins. The same electrochemical behaviour was recorded for the type 2 Cu-depleted derivatives, which contain reduced type 3 Cu, whereas the apoproteins were electrochemically inactive. Under aerobic conditions the catalytic current intensity of holoprotein voltammograms increased up to approx. 2-fold at a low scanning rate, with unchanged redox potentials. The voltammograms of type 2 Cu-depleted proteins and of apoproteins were unaffected by the presence of oxygen. This suggests that electron uptake at the electrode surface involves type 1 Cu and that only in the presence of oxygen is the intramolecular electron transfer to other protein sites rapid enough to be observed. The analogy with available kinetic results is discussed.

SI-PET-RAFT: Surface-Initiated Photoinduced Electron Transfer-Reversible Addition–Fragmentation Chain Transfer Polymerization

2019 ◽  
Vol 8 (4) ◽  
pp. 374-380 ◽  
Author(s):  
Mingxiao Li ◽  
Michele Fromel ◽  
Dhanesh Ranaweera ◽  
Sergio Rocha ◽  
Cyrille Boyer ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Chain Transfer ◽  
Reversible Addition ◽  
Chain Transfer Polymerization
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