Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.10.3.2 (laccase)
 4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on the properties of hydrogel matrix for the immobilization of laccase on conductive supports. The poly(N-isopropylacrylamide) gel is attached firmly to the indium-tin oxide (ITO) electrode, following its silanization with dimethylethoxyvinylsilane. The enzyme entrapped in the gel structure remained active longer than in the solution, and its redox and catalytic properties could be investigated by voltammetric methods. The reduction signals of the active sites, T1 and T2, of the Cerrena unicolor laccase were determined to be 0.79 and 0.38 V, respectively. The laccase catalytic activity toward oxygen in poly(N-isopropylacrylamide) was found to depend strongly on temperature. Reversible swelling/shrinking of the matrix was studied at 30 and 35 degrees C. Shrinking of the gel at higher temperature considerably decreased the efficiency of the catalytic reaction, however, interestingly, did not lead to irreversible changes in the enzyme structure. At temperatures below that corresponding to volume phase transition, the catalytic properties of the film were fully restored. High catalytic efficiency of the gel immobilized enzyme made it possible to employ the gel covered electrode for monitoring oxygen in solutions.
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PMID:Thermoresponsive poly(N-isopropylacrylamide) gel for immobilization of laccase on indium tin oxide electrodes. 1934 46

Multiwalled carbon nanotubes were entrapped in sol-gel processed hydrophilic silicate thin film on tin-doped indium oxide support. Microscopic images show that the nanotubes form large agglomerates of largely separated nanotubes covered by silicate film. The measurements of capacitive current prove that approximately 10% of them remain electrochemically active. The surface confined cyclic voltammetry indicate adsorption of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) on this material. The oxidation charge estimated after the adsorption saturated shows that this compound is adsorbed on almost all the surface of the immobilised carbon nanotubes. After further modification of the electrode with extracellular laccase from Cerrena unicolor electrocatalytic dioxygen reduction is observed. The immobilised enzyme exhibits catalytic action whereas 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) adsorbed on carbon nanotubes serves as electron mediator between protein and electrode. Bioelectrocatalysis is also observed in the absence of adsorbed mediator but the efficiency of the process is approximately one order of magnitude smaller.
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PMID:Adsorption of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) on multiwalled carbon nanotubes-silicate film: application to bioelectrocatalytic dioxygen reduction. 1943 74

Redox enzymes can be envisioned as biocatalysts in various electrocatalytic-based devices. Among factors that play roles in bioelectrochemistry limitations, the effect of enzyme-enzyme neighboring interaction on electrocatalysis has rarely been investigated, although critical in vivo. We report in this work an in-depth study of gold nanoparticles prepared by laser ablation in the ultimate goal of determining the relationship between activity and enzyme density on electrodes. Nanosecond laser interaction with nanometric gold films deposited on indium tin oxide support was used to generate in situ gold nanoparticles (AuNPs) free from any stabilizers. A comprehensive analysis of AuNP size and coverage, as well as total geometric surface vs. electroactive surface is provided as a function of the thickness of the treated gold layer. Using microscopy and electrochemistry, the long-term stability of AuNP-based electrodes in the atmosphere and in the electrolyte is demonstrated. AuNPs formed by laser treatment are then modified by thiol chemistry and their electrochemical behavior is tested with a redox probe. Finally, enzyme adsorption and bioelectrocatalysis are evaluated in the case of two enzymes, i.e., the Myrothecium verrucaria bilirubin oxidase and the Thermus thermophilus laccase. Behaving differently on charged surfaces, they allow demonstrating the validity of laser treated AuNPs for bioelectrocatalysis.
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PMID:Nanosecond Laser-Fabricated Monolayer of Gold Nanoparticles on ITO for Bioelectrocatalysis. 3258 33