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)

Polyphenol oxidase (PPO; EC 1.10.3.2) was isolated from wheat bran by a procedure that included ammonium sulfate fractionation, batch adsorption by DEAE-cellulofine, CM-cellulofine column chromatography, DEAE-cellulofine column chromatography, preparative isoelectric focusing, adsorption on the membrane of a Vivapure Q Maxi H spin column, and heat treatment. These procedures led to 150-fold purification with 4.2% recovery. The PPO was homogeneous by SDS/PAGE. The relative molecular weight of the PPO was estimated to be 37,000 based on its mobility in SDS/PAGE. The isoelectric point of the PPO was 4.4. The K(m) values of the PPO for caffeic acid, chlorogenic acid, pyrocatechol, 4-methyl catechol and l-DOPA as substrates were 0.077, 0.198, 1.176, 1.667 and 4.545 mM. The PPO was strongly inhibited by tropolone. The K(i) value for tropolone is 2.2 x 10(-7) M. The sequence of the 15 N-terminal amino-acid residues was determined to be ATDVRLSIAHQTRFA, which was identical to those of serpin from Triticum aestivum and protein Z from Hordeum vulgare. The PPO strongly inhibited the activity of trypsin, which is an enzyme of serine proteases; 50% inhibition was observed with 1.5 x 10(-7) M PPO. The K(i) value for PPO is 2.3 x 10(-8) M. The wheat bran PPO should be a very important protein for protecting wheat against disease, virus, insect and herbivore damages by both the activities of PPO and protease inhibitor.
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PMID:Polyphenol oxidase from wheat bran is a serpin. 1850 24

A recombinant laccase from Trametes versicolor in Pichia methanolica was produced constitutively in a defined medium. The recombinant laccase was purified using ultrafiltration, anion-exchange chromatography, and gel filtration. The molecular weight of the purified laccase was estimated as 64 kDa by SDS-PAGE. The purified recombinant laccase decolorized more than 90% of Remazol Brilliant Blue R (RBBR) initially at 80 mg l(-1) after 16 h at 45 degrees C and pH 5 when 25 U laccase ml(-1) was used. The purified recombinant laccase could efficiently decolorize RBBR without additional redox mediators.
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PMID:Purification of recombinant laccase from Trametes versicolor in Pichia methanolica and its use for the decolorization of anthraquinone dye. 1868 74

The production of laccases during the lag, exponential and stationary phases of growth of Pleurotus ostreatus in submerged fermentation was evaluated. Laccase activity was positively correlated to the growth of the fungus. The specific growth rate was 0.02 h(-1) and the highest amount of dry biomass (7.8 gl(-1)) was obtained after 480 h of growth. Four laccase isoforms were secreted by the fungus, and tentatively named L(I)1, L(I)2, L(I)3 and L(I)4. L(I)2, L(I)3 and L(I)4 were produced during the stationary phase (between 408 and 456 h approximately) while L(I)1 was produced during the lag, exponential and stationary phases of growth. Maximal laccase activity (12 200 Ul(-1)) was observed at the beginning of the stationary phase (at 432 h of growth). L(I)1 was purified by preparative isoelectric focusing and partially characterized. L(I)1 had a molecular mass of 43.7 kDa as determined by SDS PAGE, a Km and Vmax of 90 microM and 1.18 DeltaAbs min(-1) respectively and an isoelectric point of 2.3. L(I)1 showed activity over a broad range of pH and temperature, which may make it useful in the biodegradation of phenolic compounds present in wastewater from several industrial processes.
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PMID:Laccases of Pleurotus ostreatus observed at different phases of its growth in submerged fermentation: production of a novel laccase isoform. 1869 77

The effect of lignin containing natural substrates corn-cob, coir-dust, saw-dust, wheat straw and bagasse particles on the extracellular secretion of laccase in the liquid culture growth medium of Pleurotus sajor-caju MTCC 141 has been studied. The culture conditions for maximum secretion of laccase by Pleurotus sajor-caju MTCC 141 have been optimized. Homogeneous preparation of laccase from the culture filtrate of the fungus has been achieved using ammonium sulphate precipitation, anion exchange chromatography on DEAE and gel filtration chromatography on Sephadex G-100. The purified enzyme preparation gave a single protein band in SDS-PAGE analysis indicating a molecular weight of 90 kD. The enzymatic characteristics Km, k(cat), pH and temperature optima of the purified laccase have been determined using 2, 6-dimethoxyphenol as the substrate and have been found to be 35 micromol/L, 0.30 min(-1), 4.5 and 37 degrees C respectively. The Km values for the other substrate like catechol, m-cresol, pyrogallol and syringaldazine have also been determined which were found to be 216 micromol/L, 380 micromol/L, 370 micromol/L and 260 micromol/L respectively.
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PMID:Purification and characterization of extracellular laccase secreted by Pleurotus sajor-caju MTCC 141. 1930 77

Three new chromatographic forms of Dichomitus squalens manganese-dependent peroxidase (MnP) were isolated from wheat-straw cultures using Mono Q and connective interaction media (CIM) fast protein liquid chromatography. Enzymes revealed identical molar mass of 50 kDa (estimated by SDS-PAGE) and pI values of 3.5, however, they varied in Km values obtained for Mn2+ oxidation. The addition of wood and straw methanol extracts to the cultures showed that the production of MnPs in wheat-straw cultures was influenced rather by the type of cultivation than by phenolic compounds from lignocellulosic material which induced laccase production. The purified CIM1 MnP was able to decolorize selected azo and anthraquinone dyes more rapidly than laccase Lc1. In vitro dye decolorization showed a synergistic cooperation of MnP and laccase. In the case of CSB degradation MnP prevented from the production of a differently colored substance that could be produced after CSB degradation by laccase-HBT system.
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PMID:Implication of Dichomitus squalens manganese-dependent peroxidase in dye decolorization and cooperation of the enzyme with laccase. 1938 71

In the present investigation, performance of various laccase-membrane reactor configurations including direct enzyme contact, enzyme impregnated, immobilized enzyme and a reactor system based on laccase immobilization in chitosan membranes for decolorization of azo dye (acid black 10 BX) were examined using laccase enzyme purified from white rot fungi Pleurotus ostreatus 1804. A five-step laccase purification procedure was employed, which improved the enzymatic activity by 8.27 folds. Laccase was confirmed by comparing with the standard marker using SDS-PAGE electrophoresis, which showed molecular weight of 63 kDa. Experimental data showed that laccase has great potential for color removal without addition of external redox mediators. Various process parameters viz. aqueous phase of pH 6.0, enzyme concentration of 1.75 U/ml, dye concentration of 20 mg/L, temperature of 30 degrees C and reaction time of 120 min were optimized to achieve maximum decolorization efficiencies. Moreover, different laccase-membrane reactor configurations were tested to determine the efficacy of repeated application of laccase on dye decolorization process. Among the different reactor configurations employed, laccase encapsulated in chitosan membrane showed advantages such as short-term contact period and reusability of enzyme for a number of cycles.
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PMID:Laccase-membrane reactors for decolorization of an acid azo dye in aqueous phase: process optimization. 1954 May 48

Low-energy ion implantation was employed to breed laccase producing strain Paecilomyces sp. WSH-L07 and a mutant S152 that exhibited an activity of more than three times over the wild strain was obtained. The optimum substrate of both the wild and mutant laccases was 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate), and followed by guaiacol with optimal pH at 3.4 and 5.0, respectively, while the mutant laccase exhibited a broader active pH range. The mutant laccase had a higher optimal catalytic temperature (60-65 degrees C) than the wild one (55 degrees C), and the wild laccase deactivated rapidly when temperature increased above 55 degrees C. Furthermore, the mutant laccase was more stable under neutral and alkaline conditions. A thermostability experiment revealed that the mutant laccase was superior to the wild laccase. Both laccases were stable in the presence of metal ions, mildly inhibited by SDS (0.5 mM), EDTA (1 mM) and 1,4-dithiothreitol (0.5 mM), and almost completely inhibited by 0.1 mM NaN(3).
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PMID:Improvement of laccase production and its properties by low-energy ion implantation. 1988 75

There is no protective vaccine or effective drug against hepatitis C virus (HCV). Sustained virological response to INF/ribavirin treatment regimen has an efficiency of about 50%. Many patients worldwide have used traditional medicines and herbal medicine in particular. A laccase has been purified from oyster mushroom (Pleurotus ostreatus) to homogeneity by DEAE Affi-gel blue gel, CM-Sephadex G-50 and Sephadex G-100. The molecular weight of the laccase was about 58 kDa in SDS-PAGE. The optimum pH and temperature of the laccase activity were pH 4.0 and 60 degrees C, respectively. The activity of the enzyme increased steadily from 20 to 40 degrees C, then very slowly from 40 degrees to 60 degrees C, while the enzyme activity decreased to 9% at 90 degrees C. The activity of the laccase changed gradually over the pH range 2.0-4.0. However, the enzyme activity was totally abrogated at the pH 8 and above. Incubation of peripheral blood cells PBCs and hepatoma HepG2 cells with laccase which were then infected with HCV did not protect the cells from HCV attack and entry, while direct interaction between HCV and the laccase at the concentrations of 2.0 and 2.5 mg/ml led to a complete inhibition of virus entry after seven days of incubation. Meantime, the laccase at the concentrations of 1.0 and 1.5 mg/ml did not display any blocking activity. The potential activity of the laccase on intracellular HCV replication in infected HepG2 cells has been examined. The laccase was capable of inhibiting HCV replication at the concentrations of 1.25 and 1.5 mg/ml after first dose of treatment for four days and at the concentrations of 0.75, 1.0, 1.25 and 1.5 mg/ml after the second dose of treatment for another four days.
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PMID:Oyster mushroom laccase inhibits hepatitis C virus entry into peripheral blood cells and hepatoma cells. 2015 83

Crosslinking enzymes are frequently used in bioprocessing of dairy products. The aim of this study was to examine the effects of enzymatic crosslinking on IgE binding, allergenicity and digestion stability of beta-casein (CN). beta-CN was crosslinked by transglutaminase, tyrosinase, mushroom tyrosinase/caffeic acid and laccase/caffeic acid. The IgE binding to beta-CN was compared in vitro by CAP inhibition assay, ELISA inhibition as well as ex vivo by basophil activation assay. Crosslinked CNs were digested by simulated gastric fluid for 15 and 60 min and obtained digests analyzed for their ability to inhibit IgE binding by CAP inhibition assay and SDS-PAGE. The ability of crosslinked CNs to activate basophils was significantly reduced in seven patients in the case of CN crosslinked by laccase and moderately reduced in the case of tyrosinase/caffeic acid crosslinked CN (in two cow's milk allergy patients tested with different allergen concentrations). The response to various crosslinked CNs differed individually among patients' sera tested by ELISA inhibition assay. The presence of caffeic acid hampered digestion by pepsin, and this effect was most pronounced for the tyrosinase/caffeic acid crosslinked CN. The laccase/caffeic acid and mushroom tyrosinase/caffeic acid had the highest potential in mitigating IgE binding and allergenicity of the beta-CN out of all investigated enzymes. The presence of a small phenolic compound also increased digestion stability of beta-CN.
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PMID:Digestibility and allergenicity assessment of enzymatically crosslinked beta-casein. 2020 91

An extracellular laccase was purified from the culture medium of the non-white rot, anthracene-degrading fungal strain Fusarium solani MAS2. Both native PAGE and SDS-PAGE revealed one single band corresponding to a molecular weight of about 72 kDa. Treatment with endoglycosidase H reduced the molecular weight by 12%. The purified laccase maintained stable at pH 3-11 and up to 50 degrees C. The highest activity was detected at pH 3.0 and at 70 degrees C. The enzyme retained 46.2-97.2% of it activity in the presence of 20mM Pb(2+), Ni(2+), Cr(3+), and its activity was enhanced in the presence of 20mM Hg(2+). The laccase retained more than 50% of its activity in the presence of 5% acetone, acetonitrile, dimethyl sulphoxide (DMSO), ethanol and methanol. The kinetic constants (K(m) and k(cat)) showed that 2,6-dimethoxyphenol (DMOP) and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt (ABTS) were the more effective substrates rather than catechol and guaiacol. The novel properties of this laccase suggest its potential for biotechnological and environmental applications.
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PMID:Purification and characterization of an extracellular laccase from the anthracene-degrading fungus Fusarium solani MAS2. 2071 85


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