“Blue” laccases

Морозова, О. В.; Shumakovich, G. P.; Gorbacheva, M.A.; Shleev, Sergey; Yaropolov, A. I.

doi:10.1134/s0006297907100112

Cited by 386 publications

(331 citation statements)

References 185 publications

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“…These results are in agreement with previous reports where the maximal bioelectrocatalytic activity of Lc from different sources was observed in the temperature range 35 -50°C [41][42][43][44]. While the solubility of O 2 decreases with increasing temperature, the increase in the diffusion coefficient offsets this decrease, resulting in an increased response [37,[45][46] which is in agreement with the results reported for homogeneous ThLc catalysis which has a temperature optimum of 45°C [47]. A small peak was observed at 0.7 V. The origin of the peak is unclear, it is not related to temperature effects at 45 o C as it has been observed previously at room temperature [22,35].…”

Section: Resultssupporting

confidence: 93%

Direct electron transfer of Trametes hirsuta laccase adsorbed at unmodified nanoporous gold electrodes

Salaj-Kośla

Pöller

Schuhmann

et al. 2013

Bioelectrochemistry

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The enzyme Trametes hirsuta laccase undergoes direct electron transfer at unmodified nanoporous gold electrodes, displaying a current density of 28 A/cm 2 . The response indicates that ThLc was immobilised at the surface of the nanopores in a manner which promoted direct electron transfer, in contrast to the absence of a response at unmodified polycrystalline gold electrodes. The bioelectrocatalytic activity of ThLc modified nanoporous gold electrodes was strongly dependent on the presence of halide ions. Fluoride completely inhibited the enzymatic response, whereas in the presence of 150 mM Cl -, the current was reduced to 50% of the response in the absence of Cl -. The current increased by 40% when the temperature was increased from 20°C to 37°C. The response is limited by enzymatic and/or enzyme electrode kinetics and is 30% of that observed for ThLc co-immobilised with an osmium redox polymer. Keywords: Laccase, direct electron transfer, nanoporous gold 2 IntroductionElectron transfer (ET) reactions are ubiquitous in nature. Controlling the rate of these reactions can be of significant benefit in developing biochemical systems that utilise redox proteins and enzymes and in particular, in applications that provide power for implanted or portable electronic devices. ET can be achieved directly (direct electron transfer, DET) or by the use of mediators (mediated electron transfer, MET) to shuttle electrons between the redox centre of the enzyme and the electrode. However, mediators are unselective and can also give rise to interfering effects [1][2][3]. DET-based devices offer high selectivity and sensitivity due to the absence of mediators. In addition, devices based on DET operate at potentials close to the redox potential of the enzyme, maximising the potential difference between the cathode and anode for biofuel cell applications [2]. Moreover, DET can be used to provide detailed information on the kinetics and thermodynamics of the ET process. However, the low stability of the enzyme layer together with the long distances over which ET occurs, represent major obstacles for DET based devices. In addition, the shielding mechanism of the enzymatic redox centre by the protein shell can disrupt DET [2,4]. One approach in optimizing and enabling rapid DET is to design the electrode surface with an architecture which promotes efficient rates of ET. In this way the electrode morphology ensures the most efficient orientation of the enzymatic redox centre and facilitates communication with the electroactive surface. Porous electrodes can be used to encapsulate the enzyme within a network of cavities, shortening the distance for electron transfer to the redox active site, which will promote more efficient and rapid rates of electron transfer [5]. However, the number of redox enzymes capable of interacting directly with the electrode while catalyzing the enzymatic reaction is limited, with estimates of approximately 5% of all enzymes exhibiting such a response [6].DET in enzymes was first described in 1978 fo...

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Section: Resultssupporting

confidence: 93%

Direct electron transfer of Trametes hirsuta laccase adsorbed at unmodified nanoporous gold electrodes

Salaj-Kośla

Pöller

Schuhmann

et al. 2013

Bioelectrochemistry

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“…Laccases are oxidoreductases or multi-copper oxidases that are widely used to oxidize a variety of dye by-products by coupling reduction of oxygen to water with concomitant oxidation of the dye product substrates (Kurniawati & Nicell, 2007Morozova et al, 2007). Laccases catalyze decolorization of textile dyes either by direct oxidation or via indirect oxidation using mediators to accelerate the Detoxification of azo dyes by bacteria 7…”

Section: Oxidative Enzymesmentioning

confidence: 99%

Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations

Ibekwe

Yang

et al. 2016

Science of The Total Environment

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Azo dyes and their intermediate degradation products are common contaminants of soil and groundwater in developing countries where textile and leather dye products are produced. The toxicity of azo dyes is primarily associated with their molecular structure, substitution groups and reactivity. To avoid contamination of natural resources and to minimize risk to human health, this wastewater requires treatment in an environmentally safe manner. This manuscript critically reviews biological treatment systems and the role of bacterial reductive and oxidative enzymes/processes in the bioremediation of dye-polluted wastewaters. Many studies have shown that a variety of culturable bacteria have efficient enzymatic systems that can carry out complete mineralization of dye chemicals and their metabolites (aromatic compounds) over a wide range of environmental conditions. Complete mineralization of azo dyes generally involves a two-step process requiring initial anaerobic treatment for decolorization, followed by an oxidative process that results in degradation of the toxic intermediates that are formed during the first step. Molecular studies have revealed that the first reductive process can be carried out by two classes of enzymes involving flavin-dependent and flavin-free azoreductases under anaerobic or low oxygen conditions. The second step that is carried out by oxidative enzymes that primarily involves broad specificity peroxidases, laccases and tyrosinases. This review focuses, in particular, on the characterization of these enzymes with respect to their enzyme kinetics and the environmental conditions that are necessary for bioreactor systems to treat azo dyes contained in wastewater.

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“…In order to determine the molecular structure of the synthesized product and to assign all the 1 H and 13 C signals, 1 H-13 C HSQC and 1 H- 13 C HMBC experiments were performed (results now shown). All these findings suggested that they belong to a six carbon quinone-ring.…”

Section: Amount Of Laccase (U)mentioning

confidence: 99%

“…Laccase is a copper-containing oxidase that catalyzes reduction of molecular oxygen to water and the oxidation of a phenolic compound 13 . Also, dimerization, oligomerization, and polymerization of phenolic compounds can be obtained 8 .…”

Section: Introductionmentioning

confidence: 99%

Improvement of the Antifungal Activity Against Botrytis Cinerea of Syringic Acid, a Phenolic Acid From Grape Pomace

Mendoza

Castro

Melo

et al. 2016

J. Chil. Chem. Soc.

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The aim of this study was to improve the antifungal activity against Botrytis cinerea of syringic acid by using the enzyme laccase to synthesize a heterodimeric compound by a coupling reaction with aniline. The synthesized heterodimer is a quinone-imine like compound (2,6-dimethoxy-4-(phenylimino)benzenone), which was characterized by using 1 H and 13 C NMR, IR, and mass spectrometry. The antifungal activity of the heterodimeric compound against B. cinerea was determined in vitro and showed a higher antifungal effect than the substrates (syringic acid and aniline), inhibiting the mycelial growth with an IC 50 value of 0.14mM and delayed 2 hours the conidial germination. Also, using the fluorochrome calcofluor white, cell wall damage was observed when B. cinerea was incubated with the compound. This is the first report on antifungal activity of this type of compound against B. cinerea.

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“Blue” laccases

Cited by 386 publications

References 185 publications

Direct electron transfer of Trametes hirsuta laccase adsorbed at unmodified nanoporous gold electrodes

Direct electron transfer of Trametes hirsuta laccase adsorbed at unmodified nanoporous gold electrodes

Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations

Improvement of the Antifungal Activity Against Botrytis Cinerea of Syringic Acid, a Phenolic Acid From Grape Pomace

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