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)

White-rot fungus AH28-2, a newly isolated strain, produced effectively laccase by induction when grown on a synthetic medium. Aromatic compounds of low molecular weight had an inducing influence on laccase production and its isoenzyme compositions. The using of o-toluidine or syringic acid had the best inducing effect. Cu2+ concentration in medium had distinguished effect on laccase production. Enzyme activity was notably increased by Cu2+ and reached the maximum when Cu2+ final concentration was 5 mumol/L. Mn2+ inhibited the synthesis of laccase. Carbon and nitrogen limitation were not beneficial to laccase synthesis, while high nutrient organic medium was beneficial to the growth of cell and the synthesis of laccase. Using cellobiose as the sole carbon source, the highest level enzyme activity reached 82,923. 7 u/L under the condition of optimum fermentation with ABTS as substrate. This enzyme activity was 2.9-fold higher compared to the reported data on international references in recent years.
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PMID:[Factors of laccase producing and fermentation conditions by a new white-rot fungus AH28-2]. 1179 26

Polyvinyl alcohol (PVA) solutions (BP05 and BF17; 5.0%, wt v(-1)) were degraded by a combination of chemical (Fenton's reagent) and fungal (Phanerochaete chrysosporium) treatments. The overall degradations of BP05 and BF17 were 74.4 and 72.8%, respectively, as determined by chemical oxygen demand (COD) analysis, and 63.7% and 57.7%, respectively, as determined by total organic carbon (TOC) analysis. Increased retention times and changes in the intensity of the PVA peaks on gel permeation chromatograms indicated that PVA molecules of greater molecular weights were degraded to lower molecular weights by both the chemical and fungal treatments. The predominant enzyme secreted by P. chrysosporium in medium containing 2% (wt v(-1)) ground cereal bran in 60 mM phosphate buffer (pH 6.0) was manganese peroxidase. Neither laccase nor lignin peroxidase activity was detected. Manganese peroxidase was probably involved in the biodegradation of the PVA solutions.
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PMID:Biodegradation of polyvinyl alcohol by Phanerochaete chrysosporium after pretreatment with Fenton's reagent. 1184 67

Low temperature electron paramagnetic resonance (EPR) spectroscopy with frequencies between 95 and 345 GHz and magnetic fields up to 12 T have been used to study radicals and metal sites in proteins and small inorganic model complexes. We have studied radicals, Fe, Cu and Mn containing proteins. For S = 1/2 systems, the high frequency method can resolve the g-value anisotropy. It was used in mouse ribonucleotide reductase (RNR) to show the presence of a hydrogen bond to the tyrosyl radical oxygen. At 285 GHz the type 2 Cu(II) signal in the complex enzyme laccase is clearly resolved from the Hg(II) containing laccase peroxide adduct. For simple metal sites, the systems over S = 1/2 can be described by the spin Hamiltonian: H(S) = BgS + D[Sz2 - S(S + 1)/3 + E/D (Sx2 - Sy2)]. From the high frequency EPR the D-value can be determined directly by, (I) shifts of g(eff) for half-integer spin systems with large D-values as observed at 345 GHz on an Fe(II)-NO-EDTA complex, which is best described as S = 3/2 system with D = 11.5 cm(-1), E = 0.1 cm(-1) and gx = gy = gz = 2.0; (II) measuring the outermost signal, for systems with small D values, distant of (2S - 1) x absolute value(D) from the center of the spectrum as observed in S= 5/2 Fe(III)-EDTA. In Mn(II) substituted mouse RNR R2 protein the weakly interacting Mn(II) at X-band could be observed as decoupled Mn(II) at 285 GHz.
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PMID:The use of high field/frequency EPR in studies of radical and metal sites in proteins and small inorganic models. 1199 59

This study was performed to determine which oxidoreductive catalysts were most efficient in catalyzing the binding of 8-hydroxybentazon to soil humic substances. 8-Hydroxybentazon was completely transformed by an oxidoreductive enzyme, laccase of Myceliophthora thermophila, at pH 3.0-7.0 within 30 min. When abiotic catalysts, manganese(IV), iron(III), and aluminum oxides were used in the same pH range, 8-hydroxybentazon was completely transformed only by manganese(IV) oxide (delta-MnO2), but a relatively small amount of 8-hydroxybentazon was transformed by iron(III) oxide and aluminum oxide. The adsorption of 8-hydroxybentazon in the soil showed an H-type and coincided well with the Langmuir isotherm. To better understand the factors involved in the rapid and strong binding of 8-hydroxybentazon with soil humic substances, 8-hydroxybentazon transformation by oxidoreductive catalysts was studied in various soil conditions: air-dried, preincubated, sterilized, and iron(III) oxide and manganese(IV) oxide free. 8-Hydroxybentazon was completely transformed within 24 h in the decreasing order of preincubated, air-dried, and sterilized soils. However, little transformation was observed in the iron(III) oxide and manganese(IV) oxide free soils. These results suggest that the major catalyst responsible for the rapid and strong binding of 8-hydroxybentazon to soil humic substances is a metal oxide, manganese(IV) oxide, not a soil oxidoreductive enzyme.
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PMID:Formation of bound residues of 8-hydroxybentazon by oxidoreductive catalysts in soil. 1203 19

Our previous results have demonstrated that Phanerochaete flavido-alba decoloration, dephenolization and detoxification of olive oil mill wastewater (OMW) were associated with changes in the ligninolytic major exoenzymes accumulated in the cultures. This paper describes the effect of the two main OMW components (monomeric aromatic compounds and a major brownish polymeric pigment), on extracellular P. flavido-alba ligninolytic enzymes. Laccase was the sole ligninolytic enzyme detected in cultures containing monomeric aromatic compounds. Laccase and an acidic manganese-dependent peroxidase (MnPA, pI<2.8) were accumulated in cultures with OMW or polymeric pigment. Also, modified manganese-dependent peroxidases were observed mainly in OMW-supplemented cultures. Laccase was more stable to the effect of OMW toxic components and was accumulated in monomeric aromatic-supplemented cultures, suggesting a more important role than manganese-dependent peroxidases in OMW detoxification. Alternatively, MnPA accumulated in cultures containing the polymeric pigment seems to be more essential than laccase for degradation of this recalcitrant macromolecule by P. flavido-alba.
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PMID:Effect of olive oil mill wastewater on extracellular ligninolytic enzymes produced by Phanerochaete flavido-alba. 1207 85

Wastewater produced by the debittering process of green olives (GOW) is rich in polyphenolics and presents high chemical oxygen demand and alkalinity values. Eight white-rot fungi ( Abortiporus biennis, Dichomitus squalens, Inonotus hispidus, Irpex lacteus, Lentinus tigrinus, Panellus stipticus, Pleurotus ostreatus and Trametes hirsuta) were grown in GOW for 1 month and the reduction in total phenolics, the decolorization activity and the related enzyme activities were compared. Phenolics were efficiently reduced by P. ostreatus (52%) and A. biennis (55%), followed by P. stipticus (42%) and D. squalens (36%), but only P. ostreatus had high decolorization efficiency (49%). Laccase activity was the highest in all of the fungi, followed by manganese-independent peroxidase (MnIP). Substantial manganese peroxidase (MnP) activity was observed only in GOW treated with P. ostreatus and A. biennis, whereas lignin peroxidase (LiP) and veratryl alcohol oxidase (VAOx) activities were not detected. Early measurements of laccase activity were highly correlated ( r(2)=0.91) with the final reduction of total phenolics and could serve as an early indicator of the potential of white-rot fungi to efficiently reduce the amount of total phenolics in GOW. The presence of MnP was, however, required to achieve efficient decolorization. Phytotoxicity of GOW treated with a selected P. ostreatus strain did not decline despite large reductions of the phenolic content (76%). Similarly, in GOW treated with purified laccase from Polyporus pensitius, a reduction in total phenolics which exceeded 50% was achieved; however, it was not accompanied by a decline in phytotoxicity. These results are probably related to the formation of phenoxy radicals and quinonoids, which re-polymerize in the absence of VAOx but do not lead to polymer precipitation in the treated GOW.
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PMID:Evaluation of white-rot fungi for detoxification and decolorization of effluents from the green olive debittering process. 1211 Nov 70

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

The ability of the ligninolytic fungus Trametes trogii to degrade in vitro different xenobiotics (PCBs, PAHs and dyes) was evaluated. Either 200 ppm of a PCB mixture (Aroclor 1150) or 160 ppm of an industrial PAH mixture (10% V/V of PAHs, principal components hexaethylbenzene, naphthalene, 1-methyl naphthalene, acenaphthylene, anthracene, fluorene and phenanthrene), were added to trophophasic and idiophasic cultures growing in a nitrogen limited mineral medium (glucose/asparagine) and in a complex medium (malt extract/glucose). Gas-liquid chromatography proved that within 7 to 12 d more than 90% of the organopollutants added were removed. The decrease in absorbance at 620 nm demonstrated that cultures of this fungus were able to transform 80% of the dye Anthraquinone-blue (added at a concentration of 50 ppm) in 1.5 h. Enzyme estimations indicated high activity of laccase (up to 0.55 U/mL), as well as lower production of manganese-peroxidase. Laccase activity, detected in all the conditions assayed, could be implicated in the degradation of these organopollutants. Considering the results obtained, T. trogii seems promising for detoxification.
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PMID:Degradation of environmental pollutants by Trametes trogii. 1241 98

A white rot fungus Thelephora sp. was used for decolourization of azo dyes such as orange G (50 microM), congo red (50 microM), and amido black 10B (25 microM). Decolourization using the fungus was 33.3%, 97.1% and 98.8% for orange G, congo red and amido black 10B, respectively. An enzymatic dye decolourization study showed that a maximum of 19% orange G was removed by laccase at 15 U/ml whereas lignin peroxidase (LiP) and manganese dependent peroxidase (MnP) at the same concentration decolourized 13.5% and 10.8%, orange G, respectively. A maximum decolourization of 12.0% and 15.0% for congo red and amido black 10B, respectively, was recorded by laccase. A dye industry effluent was treated by the fungus in batch and continuous modes. A maximum decolourization of 61% was achieved on the third day in the batch mode and a maximum decolourization of 50% was obtained by the seventh day in the continuous mode. These results suggest that the batch mode of treatment using Thelephora sp. may be more effective than the continuous mode for colour removal from dye industry effluents.
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PMID:Decolourization of azo dyes and a dye industry effluent by a white rot fungus Thelephora sp. 1257 4

Despite numerous reports concerning the biodegradation of rubber materials, there has been no report of rubber degradation by fully characterized enzymes. In the present paper, we presented a new method to decompose nonvulcanized and vulcanized polyisoprene rubbers by controlling the free radical chain reactions of lipids using oxidative enzymes, manganese peroxidase (MnP), laccase (Lac), and horseradish peroxidase (HRP). Nonvulcanized synthetic polyisoprene (IR) was degraded by the free radicals from unsaturated fatty acids produced by MnP, HRP, and a combination of Lac/1-hydroxybenzotriazole. In contrast, lipoxygenase caused no apparent degradation. Degradation of IR was also observed in lipid peroxidation initiated by the Fenton reaction (FR) and Mn(III), an oxidation product produced by MnP. Vulcanized polyisoprene rubber sheets were degraded by the lipid peroxidation initiated by HRP, MnP, Mn(III), and FR. Pyrolysis GC-MS analysis demonstrated that the lipid peroxidation liberated isoprenoid fragments from the vulcanized rubbers.
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PMID:Degradation of vulcanized and nonvulcanized polyisoprene rubbers by lipid peroxidation catalyzed by oxidative enzymes and transition metals. 1262 27


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