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)

The white rot basidiomycete Trametes (Coriolus) versicolor can substantially increase the brightness and decrease the lignin content of washed, unbleached hardwood kraft pulp (HWKP). Monokaryotic strain 52J was used to study how HWKP and the lignin in HWKP affect the carbon metabolism and secretions of T. versicolor. Earlier work indicated that a biobleaching culture supernatant contained all components necessary for HWKP biobleaching and delignification, but the supernatant needed frequent contact with the fungus to maintain these activities. Thus, labile small fungal metabolites may be the vital biobleaching system components renewed or replaced by the fungus. Nearly all of the CO(2) evolved by HWKP-containing cultures came from the added glucose, indicating that HWKP is not an important source of carbon or energy during biobleaching. Carbon dioxide appeared somewhat earlier in the absence of HWKP, but the culture partial O(2) pressure was little affected by the presence of pulp. The presence of HWKP in a culture markedly increased the culture's production of a number of acidic metabolites, including 2-phenyllactate, oxalate, adipate, glyoxylate, fumarate, mandelate, and glycolate. Although the total concentration of these pulp-induced metabolites was only 4.3 mM, these compounds functioned as effective manganese-complexing agents for the manganese peroxidase-mediated oxidation of phenol red, propelling the reaction at 2.4 times the rate of 50 mM sodium malonate, the standard chelator-buffer. The presence of HWKP in a culture also markedly stimulated fungal secretion of the enzymes manganese peroxidase, cellulase, and cellobiose-quinone oxidoreductase, but not laccase (phenol oxidase) or lignin peroxidase.
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PMID:Effects of Kraft Pulp and Lignin on Trametes versicolor Carbon Metabolism. 1634 63

The production of the H(2)O(2)-generating enzyme pyranose oxidase (POD) (EC 1.1.3.10) (synonym, glucose 2-oxidase), two ligninolytic peroxidases, and laccase in wood decayed by three white rot fungi was investigated by correlated biochemical, immunological, and transmission electron microscopic techniques. Enzyme activities were assayed in extracts from decayed birch wood blocks obtained by a novel extraction procedure. With the coupled peroxidase-chromogen (3-dimethylaminobenzoic acid plus 3-methyl-2-benzothiazolinone hydrazone hydrochloride) spectrophotometric assay, the highest POD activities were detected in wood blocks degraded for 4 months and were for Phanerochaete chrysosporium (149 mU g [dry weight] of decayed wood), Trametes versicolor (45 mU g), and Oudemansiella mucida (1.2 mU g), corresponding to wood dry weight losses of 74, 58, and 13%, respectively. Mn-dependent peroxidase activities in the same extracts were comparable to those of POD, while lignin peroxidase activity was below the detection limit for all fungi with the veratryl alcohol assay. Laccase activity was high with T. versicolor (422 mU g after 4 months), in trace levels with O. mucida, and undetectable in P. chrysosporium extracts. Evidence for C-2 specificity of POD was shown by thin-layer chromatography detection of 2-keto-d-glucose as the reaction product. By transmission electron microscopy-immunocytochemistry, POD was found to be preferentially localized in the hyphal periplasmic space of P. chrysosporium and O. mucida and associated with membranous materials in hyphae growing within the cell lumina or cell walls of partially and highly degraded birch fibers. An extracellular distribution of POD associated with slime coating wood cell walls was also noted. The periplasmic distribution in hyphae and extracellular location of POD are consistent with the reported ultrastructural distribution of H(2)O(2)-dependent Mn-dependent peroxidases. This fact and the dominant presence of POD and Mn-dependent peroxidase in extracts from degraded wood suggest a cooperative role of the two enzymes during white rot decay by the test fungi.
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PMID:Pyranose Oxidase, a Major Source of H(2)O(2) during Wood Degradation by Phanerochaete chrysosporium, Trametes versicolor, and Oudemansiella mucida. 1634 30

A family of genes encoding laccases has recently been described for the basidiomycete I-62 (CECT 20197). Transcript levels of genes lcc1, lcc2, and lcc3 were analyzed under four different culture conditions to study their expression patterns. Two of the laccase genes were clearly inducible by veratryl alcohol: the lcc1 gene is inducible in early stages of growth, and the lcc2 gene is also inducible but only when the organism reaches the stationary phase. Transcript levels for the third gene, lcc3, were uninduced by veratryl alcohol and repressed by glucose.
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PMID:Differential Gene Expression in the Laccase Gene Family from Basidiomycete I-62 (CECT 20197). 1634 7

While studying the interaction of Cryptococcus neoformans with Dictyostelium discoideum, we noticed that yeast colonies in agar with a feeder lawn of Klebsiella aerogenes were brown. This finding was intriguing because C. neoformans colonies are not pigmented unless they are provided with precursors for melanization. Strains of all C. neoformans serotypes produced brown pigment in response to K. aerogenes at 22, 30, and 37 degrees C. Pigment production required fungal laccase and was suppressed by high concentrations of glucose. Treatment of brown cells with guanidinium isothiocyanate and hot concentrated HCl yielded particulate material that had the physical and chemical characteristics of melanins. No pigment formation was observed when C. neoformans was exposed to live Escherichia coli or heat-killed K. aerogenes. Analysis of K. aerogenes supernatants revealed the presence of dopamine, which can be a substrate for melanin synthesis by C. neoformans. Our findings illustrate a remarkable interaction between a pathogenic fungus and a gram-negative bacterium, in which the bacterium produces a substrate that promotes fungal melanization. This observation provides a precedent that could explain the source of a substrate for C. neoformans melanization in the environment.
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PMID:Induction by Klebsiella aerogenes of a melanin-like pigment in Cryptococcus neoformans. 1646 9

An isolate of Botrytis cinerea (strain 61-34) constitutively expresses substantial amounts of extracellular laccase on a defined growth medium. The enzyme has been purified to homogeneity by a facile operational sequence, the last stage of which involves hydrophobic interaction chromatography. By these means, over 80 mg of laccase liter(sup-1) can be obtained from aerated fermentor reaction broths. The enzyme, with an estimated M(infr) of 74,000 and pI of 4.0, is a monomeric glycoprotein containing 49% carbohydrate predominantly as hexose. With 2,6-dimethoxyphenol, it exhibits a pH optimum of 3.5 and a temperature optimum of 60(deg)C, and its K(infm) is 100 (mu)M. The purified enzyme with this substrate has a specific activity of 9.1 mkat mg of protein(sup-1). Taken together with a broad substrate range and its stability in 4% sodium dodecyl sulfate or 2 M urea solutions, several biotechnology transfers are suggested.
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PMID:Production and Characterization of Laccase from Botrytis cinerea 61-34. 1653 74

(sup14)C-synthetic lignin mineralization by the basidiomycete Ceriporiopsis subvermispora occurs at the highest rate (about 30% after 29 days) in liquid cultures containing 1% glucose and a growth-limiting amount (1 mM) of ammonium tartrate. The titers of manganese peroxidase (MnP) and laccase are lower in these cultures than in cultures containing 1% glucose and 10 mM ammonium tartrate, where the extent of lignin mineralization in the same period is only about 15%. The inverse correlation between enzyme activity and lignin mineralization is also observed when ammonium tartrate is replaced by ammonium chloride or Casamino Acids as the source of nitrogen. This phenomenon can be explained by a gradual increase in the pH of the medium that takes place only in the cultures with high nitrogen concentrations. Supporting this finding, when cultures with 1 mM ammonium tartrate were grown at different pHs, (sup14)CO(inf2) evolved more rapidly from those with pH values near the optimum for MnP activity. On the other hand, (sup14)CO(inf2) evolution from cultures containing 1% glucose supplemented with 1 mM ammonium tartrate plus 9 mM sodium tartrate was as low as that from cultures with a high ammonium tartrate concentration. Since the changes in the pH of these cultures were not as pronounced as those in cultures containing high nitrogen concentrations, tartrate itself may also be contributing to limit the extent of lignin mineralization. Considering that pH instability seems to constitute a common feature of fungal cultures, precautions must be taken to avoid underestimation of their ligninolytic efficiencies.
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PMID:Synthetic Lignin Mineralization by Ceriporiopsis subvermispora Is Inhibited by an Increase in the pH of the Cultures Resulting from Fungal Growth. 1653 66

The white rot fungus Phlebia radiata 79 (ATCC 64658) produces lignin peroxidase (LiP), manganese peroxidase (MnP), glyoxal oxidase (GLOX), and laccase in the commonly used glucose low-nitrogen liquid medium. However, the enzymes which this fungus utilizes for selective removal of lignin during degradation of different lignocellulosic substrates have not been studied before. Multiple forms of LiP, MnP, GLOX, and laccase were purified from P. radiata culture extracts obtained after solid-state fermentation of wheat straw. However, the patterns of extracellular lignin-modifying enzymes studied were different from those of the enzymes usually found in liquid cultures of P. radiata. Three LiP isoforms were purified. The major LiP isoform from solid-state cultivation was LiP2. LiP3, which has usually been described as the major isoenzyme in liquid cultures, was not expressed during straw fermentation. New MnP isoforms have been detected in addition to the previously reported MnPs. GLOX was secreted in rather high amounts simultaneously with LiP during the first 2 weeks of growth. GLOX purified from P. radiata showed multiple forms, with pIs ranging from 4.0 to 4.6 and with a molecular mass of ca. 68 kDa.
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PMID:Lignin Peroxidases, Manganese Peroxidases, and Other Ligninolytic Enzymes Produced by Phlebia radiata during Solid-State Fermentation of Wheat Straw. 1653 39

In recent years, use of microbial biomass for decolourization of textile industry wastewater is becoming a promising alternative in which some bacteria and fungi are used to replace present treatment processes. Saccharomyces cerevisiae MTCC 463 decolourized the triphenylmethane dyes (malachite green, cotton blue, methyl violet and crystal violet) by biosorption, showing different decolourization patterns. However, malachite green decolourized by biosorption at the initial stage and further biodegradation occurred, about 85% in plain distilled water within 7 h, and about 95.5% in 5% glucose medium within 4 h, under aerobic conditions and at room temperature. Decolourization of malachite green depends on various conditions, such as concentration of dye, concentration of cells, composition of medium and agitation. HPLC, UV-VIS, FTIR and TLC analysis of samples extracted with ethyl acetate from decolourized culture flasks confirmed the biodegradation of malachite green into several metabolites. A study of the enzymes responsible for the biodegradation of malachite green in the control and cells obtained after decolourization showed the activities of laccase, lignin peroxidase, NADH-DCIP reductase, malachite green reductase and aminopyrine N-demethylase in control cells. A significant increase in the activities of NADH-DCIP reductase and MG reductase was observed in the cells obtained after decolourization, indicating a major involvement of reductases in malachite green degradation.
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PMID:Biotransformation of malachite green by Saccharomyces cerevisiae MTCC 463. 1654 73

The successful bioremediation of a phenolic wastewater by Trametes versicolor was found to be dependent on a range of factors including: fungal growth, culture age and activity and enzyme (laccase) production. These aspects were enhanced by the optimisation of the growth medium used and time of addition of the pollutant to the fungal cultures. Different media containing 'high' (20 g/L), 'low' (2 g/L) and 'sufficient' (10 g/L) concentrations of carbon and nitrogen sources were investigated. The medium containing both glucose and peptone at 10 g/L resulted in the highest Growth Related Productivity (the product of specific yield and micro) of laccase (1.46 Units of laccase activity)/gram biomass/day and was used in all further experiments. The use of the guaiacol as an inducer further increased laccase activity 780% without inhibiting growth; similarly the phenolic effluent studied boosted activity almost 5 times. The timing of the addition of the phenolic effluent was found to have important consequences in its removal and at least 8 days of prior growth was required. Under these conditions, 0.125 g phenol/g biomass and 0.231 g o-cresol/g biomass were removed from solution per day.
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PMID:Improving the bioremediation of phenolic wastewaters by Trametes versicolor. 1654 62

Phellinus robustus produced both laccase (700-4,000 U l(-1)) and manganese peroxidase (MnP) (1,000-11,300 U l(-1)) in fermentation of nine food wastes, whereas Ganoderma adspersum produced only laccase (600-34,000 U l(-1)). Glucose provided high laccase and MnP activity of P. robustus but repressed enzyme production by G. adspersum. Ammonium sulphate and ammonium tartrate increased the P. robustus laccase yield (3-fold), whereas the accumulation of MnP was not enhanced by additional nitrogen.
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PMID:Laccase and manganese peroxidase activities of Phellinus robustus and Ganoderma adspersum grown on food industry wastes in submerged fermentation. 1682 99


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