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)

Yellow and blue forms of laccase from solid-state and submerged cultures of Panus tigrinus were isolated. Both laccases had similar molecular masses and specific activity, but yellow laccase had no 'blue' maximum in the absorption spectrum. Blue laccase oxidized veratryl alcohol and a nonphenolic dimeric lignin model compound only in the presence of 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) as electron-transfer mediator. Yellow laccase catalyzed these reactions without any additional compounds. It is supposed that yellow laccase is formed as a result of blue laccase modification by products of lignin degradation. These compounds might play a role of natural electron-transfer mediators for the oxidation of non-phenolic substances, catalyzed by yellow laccase.
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PMID:'Yellow' laccase of Panus tigrinus oxidizes non-phenolic substrates without electron-transfer mediators. 930 53

Blue laccase from Coriolus versicolor and blue and yellow laccases from Panus tigrinus were isolated, purified and studied in acetate buffer solutions, with and without addition of various amounts of ethanol, using syringaldazine and 2,6-dimethoxyphenol as substrates. Effect of ethanol on blue laccases could be successfully described using the mixed inhibition model, over the range of 0-2.5 M ethanol concentrations. Yellow laccase from P. tigrinus behaves differently, which may be explained by the presence of some extra molecules in its structure, which possibly stabilize the enzyme and might be exchanged in ethanol solutions.
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PMID:Effect of ethanol on enzymatic activity of fungal laccases. 1084 Dec 75

We have investigated transformation of eight industrial dyes by a white-rot fungus, Trametes versicolor. The fungus was found to decolorize Reactive Golden Yellow R, Procion Red, Reactive Violet 5, Reactive Blue 28, and Ponceau Red 4R at an initial dye concentration of 80 ppm within 72 h of incubation, whereas it took 5 d to completely decolorize Reactive Black 5 (40 ppm). However, it did not significantly decolorize Reactive Red 152 and Novatic Blue BC S/D. During decolorization in liquid medium, laccase and manganese-independent peroxidase (MiP) activities were detected in culture filtrate of T. versicolor. Dye-decolorizing activity of the culture was found to be associated with H2O2-dependent activity of the culture filtrate. Furthermore, dye-decolorizing activity of the culture filtrate was not influenced by Mn2+ or veratryl alcohol, thus suggesting a role of extracellular MiP in decolorization of synthetic dyes by T. versicolor.
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PMID:Transformation of textile dyes by white-rot fungus Trametes versicolor. 1239 14

A laccase-mediator system (LMS) for biobleaching was applied to a bleached chemical pulp dyed with stilbene dye Direct Yellow 11. Of mediators tested, 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) was found to be more effective than either violuric acid (VA) or N-hydroxybenzotriazole (HBT), which had been shown to be superior to ABTS when bleaching virgin chemical pulp. The laccase-ABTS system removed more than 60% of the color.
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PMID:Laccase-mediator biobleaching applied to a direct yellow dyed paper. 1557 30

A stilbene dye (Direct Yellow 11) and a methine dye, Basazol 46L, recalcitrant to common chemical bleaches, were treated with horseradish and soybean peroxidases. Both enzymes were effective at chromophore removal. When compared to laccase in combination with a mediator (ABTS), soybean peroxidase was more effective at oxidative dye removal, especially for the methine dye.
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PMID:Enzymatic biobleaching of two recalcitrant paper dyes with horseradish and soybean peroxidase. 1608 55

Yellow laccase was isolated from a solid-phase culture of the fungus Pleurotus ostreatus D1 and characterized. It is a copper-containing enzyme with molecular weight 64 kDa. Its absorption spectrum lacks the maximum at 610 nm, characteristic of fungal laccases and corresponding to type I copper atom. The optimum pH values for the enzyme were determined. They proved to be: 7.0 for syringaldazine, 8.0 for pyrocatechol, and 4.0 for 2,2'-azine-bis-(3-ethylbenzothiazoline-6-sulfonate and 2,6-dimethoxyphenol. Kinetic parameters (Km and Vmax) for oxidation of these substrates were determined. The effect of inhibitors (SDS, 2-mercaptoethanol, and EDTA) on the activity of the enzyme was studied. It was shown that yellow laccase from Pleurotus ostreatus D1 oxidized anthracene to anthraquinone by 95% without any mediator.
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PMID:[Yellow laccase from the fungus Pleurotus ostreatus D1: purification and characterization]. 1652 79

A kinetic model based on Michaelis-Menten equation was developed to simulate the dye decolourisation of Reactive Black 5 (RB5), Reactive Blue 114 (RB114), Reactive Yellow 15 (RY15), Reactive Red 239 (RR239) and Reactive Red 180 (RR180) dyes by commercial laccase. The unusual kinetic behavior of some of these reactions suggests that the kinetic model must consider the activation of the laccase-mediator system. Several reactions at different concentrations of each dye were performed in batch reactors and time courses were obtained. A LSODE code to solve the differential equation obtained from the batch reactor was combined with an optimization Fortran program to obtain the theoretical time courses. The time courses obtained from the developed program were compared with the experimentally obtained ones to estimate the kinetic constants that minimized the difference between them. The close correlation between the predicted and the experimental results seems to support the reliability of the established models.
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PMID:Kinetic modelling and simulation of laccase catalyzed degradation of reactive textile dyes. 1798 93

Degradation of a mixture of three reactive textile dyes (Reactive Black 5, Reactive Yellow 15 and Reactive Red 239), simulating a real textile effluent, by commercial laccase, was investigated in a batch reactor. The discoloration was appraised as a percentage of the absorbance reduction at the wavelength of maximum absorbance for each dye and as total color removal based in all visible spectrum. A significantly high discoloration was achieved in both cases, indicating the applicability of this method for textile wastewater treatment. Mathematical models were developed to simulate the kinetics of laccase catalyzed degradation of reactive dyes in mixtures. Like in single dye degradation, some of the reactions present an unusual kinetic behavior, corresponding to the activation of the laccase-mediator system. The kinetic constants of the models were estimated by minimizing the difference between the predicted and the experimental time courses. Although not perfect, the ability of the models in representing the experimental results suggests that they could be used in design and simulation applications.
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PMID:Modeling the discoloration of a mixture of reactive textile dyes by commercial laccase. 1880 17

Biocatalytic treatment of a synthetic dye house effluent, simulating a textile wastewater containing various reactive dyestuffs (Reactive Yellow 15, Reactive Red 239 and Reactive Black 5) and auxiliary chemicals, was investigated in a batch reactor using a commercial laccase. A high decolourisation (above 86%) was achieved at the maximum wavelength of Reactive Black 5. The decolourisation at the other dyes wavelengths (above 63% for RY15 and around 41% for RR239) and the total decolourisation based on all the visible spectrum (around 55%) were not so good, being somewhat lower than in the case of a mixture of the dyes (above 89% for RB5, 77% for RY15, 68% for RR239 and above 84% for total decolourisation). Even so, these results suggest the applicability of this method to treat textile dyeing wastewaters. Kinetic models were developed to simulate the synthetic effluent decolourisation by commercial laccase. The kinetic constants of the models were estimated by minimizing the difference between the predicted and the experimental time courses. The close correlation between the experimental data and the simulated values seems to demonstrate that the models are able to describe with remarkable accuracy the simulated effluent degradation. Water quality parameters such as TOC, COD, BOD(5) and toxicity were found to be under the maximum permissible discharge limits for textile industries wastewaters.
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PMID:Treatment and kinetic modelling of a simulated dye house effluent by enzymatic catalysis. 1964 98

In vitro culture plants of Typhonium flagelliforme were found to decolorize a variety of dyes, including Malachite Green, Red HE 8B, Methyl Orange, Reactive Red 2, Direct Red 5B (DR5B), Red HE 7B, Golden Yellow HER, Patent Blue, and Brilliant Blue R (BBR), to varying extents within 4 days. The enzymatic analysis of plant roots of aseptically raised plantlets performed before and after degradation of the dye BBR by these plantlets showed a significant induction in the activities of peroxidase, laccase, tyrosinase, and 2,6-dichlorophenol-indophenol reductase, which indicated the involvement of these enzymes in the metabolism of the dye. Comparative study of the enzyme status of the plants Typhonium flagelliforme and Blumea malcolmii during the degradation of DR5B and BBR showed marked variations in the enzyme profile with respect to the use of different sources of the enzyme. Phytoremediation of BBR using Typhonium flagelliforme was confirmed with high performance liquid chromatography and Fourier transform infrared spectroscopy analysis performed before and after the degradation of the dye. One of the products of the metabolism of the dye was identified as 4-(4-ethylimino-cyclohexa-2,5-dienylidinemethyl)-phenylamine with the aid of gas chromatography-mass spectroscopy (GC-MS) analysis. Significant decrease in the American Dye Manufacturer's Institute, biological oxygen demand, and chemical oxygen demand values of synthetic mixture of textile dyes and industrial effluent confirmed the decolorization and detoxification. Phytotoxicity studies also revealed the nontoxic nature of the metabolites of BBR.
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PMID:Studies on phytoremediation potentiality of Typhonium flagelliforme for the degradation of Brilliant Blue R. 2043 82


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