Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Mycelia Sterilia YY-5, an entophytic fungus, was isolated from Rhus chinensis Mill and its extracellular enzyme had a higher laccase activity (MS-Lac). After been purified by anion exchange and gel filtration chromatography, MS-Lac, which had a molecular mass of 45 kDa, was found to be an alkali-stable enzyme with an optimum pH of 10.0 and capable of retaining 80% activity after incubation for 72 h with syringaldazine as substrate. It was also found that syringaldazine had a higher affinity than 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulphonate (ABTS) as substrate for MS-Lac, which was determined in sodium phosphate buffer (pH 6.0, 0.1M) at 30 degrees C. Meanwhile, the lignin modification, catalyzed by MS-Lac, indicated that it could oxidize the phenolic hydroxyl, side chain substituent or carbonyl group of spruce alkali lignin in cetyltrimethylammonium bromide (CTAB) reversed micelles (20 mM, pH 6.0, W/O=40) and steam-exploded wheat straw alkali lignin in NaOH solution (20 mM, pH 10.0).
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PMID:An alkali-stable enzyme with laccase activity from entophytic fungus and the enzymatic modification of alkali lignin. 1809 84

Surface hydrophobicity (SH) of milk proteins treated physicochemically (by heating and Maillard reaction) or modified enzymatically (by transglutaminase, lactoperoxidase, laccase, and glucose oxidase) was assessed in relation to their techno-functional properties. Heat-treatment increased SH of whey protein isolate and decreased SH of sodium caseinate and bovine serum albumin. Maillard reaction of milk proteins caused time-depended decreases of SH. Only for total milk protein reacting with glucose and lactose elevated SH-values were detected. Protein modification with transglutaminase, laccase, and lactoperoxidase strongly increased the SH of whey protein isolate and total milk protein. Incubation with glucose oxidase elevated SH values of sodium caseinate, whey protein isolate, and total milk protein. When correlating SH with techno-functional properties, a positive correlation was observed between SH and foam formation, and a negative correlation was observed between SH and foam stability as well as emulsion stability. No clear correlation was detected between SH and emulsifying activity, surface tension, viscosity, and heat stability of enzymatically and physicochemically treated milk proteins.
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PMID:Surface hydrophobicity of physicochemically and enzymatically treated milk proteins in relation to techno-functional properties. 1816 64

Soil samples collected from the vicinity of "Manpasand textile industry", located near Ichalkaranji, India were studied for screening and isolation of bacterial strains capable of degradation of textile dyes. A potential strain was selected on the basis of rapid dye degradation and later identified as Comamonas sp. UVS. Comamonas sp. UVS showed 100% decolorization of Direct Red 5B (DR5B) dye at 40 degrees C and pH 6.5. The maximum Direct Red 5B concentration decolorized was 1,100 mg/l in nutrient broth within 125 h. A numerical simulation with the Michaelis-Menten kinetics model gives an optimal value of 16.01+/-0.36 mg dye/g cell/h for maximum rate (V(max)) and 7.97+/-0.21 mg/l for the Michaelis constant (K(m)). The induction in the activities of laccase and LiP was observed during decolorization. These enzymes were inhibited by the addition of sodium azide. The biodegradation was monitored by UV-vis, FTIR spectroscopy and HPLC. The GCMS analysis indicated the presence of 7-benzoylamino-3-diazenyl-4-hydroxy-naphthalene-2-sulfonic acid in degraded product of the dye. The germination of Triticum aestivum seeds was inhibited with DR5B treatment but not with the treatment of dye degradation products.
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PMID:Biodegradation of Direct Red 5B, a textile dye by newly isolated Comamonas sp. UVS. 1832

A full length cDNA encoding an extracellular laccase was isolated by reverse transcription polymerase chain reaction from the mycelia of the mushroom Pleurotus eryngii. The isolated sequence, denoted Ery3, encodes for a mature laccase isoenzyme of 531 amino acid residues with a predicted molecular weight of 56.6 kDa. All sequence motifs, being the signature sequences used to identify the laccases, were found in the Ery3 protein sequence. The Ery3 cDNA was expressed in Saccharomyces cerevisiae and the effects of copper concentration and cultivation temperature were investigated. S. cerevisiae cells were immobilized in calcium alginate gel and the optimal immobilization parameters for the enhanced production of laccase were determined. The immobilization was most effective with 3% sodium alginate, 0.1 M calcium chloride and an initial biomass of 4.5 x 10(8) cells. The enzyme yield obtained with immobilized cells (139 mU ml(-1)) showed a 1.6-fold increase compared to the highest yield obtained with free cells. The alginate beads showed good stability and retained 84% capacity of enzyme production after seven repeated cycles of batch fermentation. The immobilization system proved to increase the proteolytic stability of the recombinant Ery3 protein. To our knowledge, this is the first report on S. cerevisiae whole-cell immobilization for recombinant laccase production.
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PMID:Molecular cloning and heterologous expression of a laccase gene from Pleurotus eryngii in free and immobilized Saccharomyces cerevisiae cells. 1844 81

A laccase was isolated from the culture filtrate of basidiomycete Fomitella fraxinea. The enzyme was purified to electrophoretical homogeneity using ammonium sulfate precipitation, anion-exchange chromatography, and gel-filtration chromatography. The enzyme was identified a monomeric protein with a molecular mass of 47 kDa sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel-filtration chromatography, and had an isoelectric point of 3.8. The N-terminal amino acid sequence for the enzyme was ATXSNXKTLAAD, which had a very low similarity to the sequences previously reported for laccases from other basidiomycetes. The optimum and temperature for 2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulfonate) (ABTS) were 3.0 and 70 degrees C, respectively. The enzyme also showed a much higher level of specific activity for ABTS and 2,6-dimethoxyphenol (DMP), where the values of the enzyme for ABTS and 2,6-DMP were 270 and 426 microM, respectively, and the Vmax values were 876 and 433.3 microM/min, respectively. The laccase activity was completely inhibited by L-cysteine, dithiothreitol (DTT), and sodium azide, significantly inhibited by Ni+, Mn+ and Ba+2, and slightly stimulated by K+ and Ca+2.
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PMID:Purification and characterization of laccase from basidiomycete Fomitella fraxinea. 1846 59

A method of enzymatic synthesis of electroconductive polyaniline on the micelles of dodecylben-zenesulfonic acid sodium salt (DBSNa) is proposed. The high potential laccase from the basidiomycete Trametes hirsuta was used as a biocatalyst. The conditions for polyaniline synthesis were optimized (pH 4.0; reagent concentrations, 10-20 mM; and aniline/DBSNa ratio, 2: 1). The resulting product was electrochemically active in the range of potentials from -200 to 600 mV, electroconductive, and capable of reversible dedoping with a change in pH of solution.
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PMID:[Micellar laccase-catalyzed synthesis of electroconductive polyaniline]. 1866 52

Fungal laccases (benzenediol:oxygen oxidoreductase, EC 1.10.3.2) from Pycnoporus cinnabarinus and Myceliophthora thermophila were used as biocatalysts for enzymatic reaction of halogen-, alkyl-, alkoxy-, and carbonyl-substituted p-hydroquinones (laccase substrates) with p-aminobenzoic acid (no laccase substrate). During this reaction, the laccase substrate was oxidized to the corresponding quinones, which react with p-aminobenzoic acid by amination of the laccase substrate. The different substitutions at the hydroquinone substrates were used to prove whether the substituents influence the position of amination and product yields. The cross-coupling of methoxy-p-hydroquinone (alkoxylated) and 2,5-dihydroxybenzaldehyd (carbonyl-substituted) with p-aminobenzoic acid resulted in the formation of one monoaminated product (yield alkoxylated 52%). If monohalogen- or monoalkyl-substituted p-hydroquinones were used as laccase substrates, two monoaminated products (constitution isomers) were formed. The simultaneous formation of two different monoaminated products from the same hydroquinone substrate is the first report for laccase-mediated synthesis of aminated constitution isomers. Depending from the type of substituent of the hydroquinone, the positions of the two monoaminations are different. While the amination at the monoalkylated hydroquinone occurs at the 5- and 6-positions (yield 38%), the amination at monohalogenated hydroquinones was detectable at the 3- and 5-positions (yield 53%). The same product pattern could be achieved if instead of the biocatalyst laccase the chemical catalyst sodium iodate was used as the oxidant. However, the yields were partially much lower (0-45% of the yields with laccase).
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PMID:Laccase-induced C-N coupling of substituted p-hydroquinones with p-aminobenzoic acid in comparison with known chemical routes. 1866 39

In company with the development of nonaqueous enzymology, the enzymatic modification of lignin has gained increasing interests, especially in the synthesis of high molecular material. In the present article, the enzymatic modification of spruce alkali lignin in cetyltrimethylammonium bromide (CTAB) reversed micelles (100 mmol x L(-1) 1, pH 6.0, W/O = 40), alcohol lignin in ethanol solution (50%), lignin sulphonate in sodium phosphate buffer (pH 5.8, 20 mmol x L(-1)) and steam-explosion wheat straw alkali lignin in alkaline solution (pH 10.0, 20 mmol x L(-1) NaOH) by mycelia sterilia YY-5 laccase was studied. Laccase was isolated from Mycelia Sterilia YY-5 (CGMCC-1462) which was an entophytic fungus of Rhus Chinensis Mill. FTIR spectrum was used to assay the structure of lignins and gel permeation chromatography (GPC) was used to determine the molecular weight and molecular weight polydispersity of lignins. Bands of lignin in FTIR spectra of all lignins changed obviously after treated with YY-5 laccase, which indicated that some bond breakage or rearrangement occurred to lignin. The shift of non-conjugated C=O and conjugated carbonyl groups (alpha-carbonyl groups) stretching vibration, the decrease of phenol hydroxyl stretching vibration and the increase of C--O--C stretching vibration of ester bond proved that phenolic hydroxyl, carbonyl group and side chain substituent all might participate in the laccase modification reactions of lignin. Meanwhile, the results of GPC indicated that the molecular of lignins all have certain increase and molecular polydispersity decreased. From the point of the molecular mass polydispersity, the modification effect of YY-5 laccase on steam-exploded wheat straw alkali lignin and spruce alkali lignin was more significantly than other two lignins. The molecular mass polydispersity for steam-exploded wheat straw alkali lignin and spruce alkali lignin was 1.211 and 1.375 respectively, which might contribute to the alkali-stable enzyme for YY-5 laccase. Correspondingly, alkali solution was chosen as the optimum medium for YY-5 laccase to modify lignins.
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PMID:[FTIR spectra analysis of the reactive activity of lignin when modified by laccase]. 1884 48

ABSTRACT Observations using light microscopy showed that approximately 30% of Botrytis cinerea conidia treated with semi-lethal concentrations (i.e., 60 mug/ml) of the grapevine phytoalexin resveratrol possessed intracellular brown coloration. This coloration was never observed in the absence of resveratrol or in conidia treated with resveratrol together with sulfur dioxide (antioxidant compound) or sodium diethyldithiocarbamate (inhibitor of laccase action), suggesting that discoloration resulted from the laccase-mediated oxidation of resveratrol. Further studies using transmission electron microscopy enabled the observation of particular intravacuolar spherical vesicles and of granular material deposits along the tonoplast. These observations are likely to be related to the oxidation of resveratrol by an intracellular laccase-like stilbene oxidase of B. cinerea.
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PMID:Resveratrol Oxidation in Botrytis cinerea Conidia. 1894 29

The priority pollutant lists of both the U.S. Environmental Protection Agency (U.S. EPA) and the European Union (EU) include diphenylamine (DPA), a contaminant found in wastewater of various industries. This work demonstrates the potential of using enzymatic treatment to remove DPA from buffered synthetic wastewater. This treatment method includes oxidative polymerization of DPA using laccase from Trametes villosa, followed by removal of those polymers via adsorptive micellar flocculation (AMF) using sodium lauryl sulfate (SDS) and alum. Researchers investigated the effects of pH, laccase concentration, molecular mass, and concentration of polyethylene glycol (PEG) in continuously stirred batch reactors to achieve 95% substrate conversion in three hours. Treatment of 0.19 mM DPA was best at pH 7 and an enzyme concentration from 0.0025 to 0.0075 standard activity unit/mL. Except for PEG400 optimum enzyme and PEG concentrations decreased with an increase in PEG molecular mass. Optimum AMF conditions were pH 3.0 to 6.5, 200 mg/L of SDS, and 150 mg/L of alum.
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PMID:Laccase-catalyzed removal of diphenylamine from synthetic wastewater. 1902 27


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