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)

A new immunochemical reagent is proposed which contains laccase, isolated from the culture liquid of the basidial fungus Coriolus hirsutus, as a marker enzyme. The feasibility of immunolaccase conjugates for different variants of immunoassay, i.e. "sandwich", competitive and indirect, is demonstrated. The comparison of immunolaccase and immunoperoxidase conjugates showed that the absolute sensitivity of laccase-antibody conjugates was 3 times higher than that of antibody-peroxidase conjugates (7.7 x 10(-11) M and 2.3 x 10(-10) M, respectively). The assay based on antibody-laccase conjugates is simpler than that employing antibody-peroxidase conjugates, since in the former case air oxygen in used as the second substrate of the enzymatic reaction.
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PMID:[Laccase from Coriolus hirsutus--a new marker enzyme for immunoenzyme analysis]. 851 77

Lignin peroxidase is generally considered to be a primary catalyst for oxidative depolymerization of lignin by white-rot fungi. However, some white-rot fungi lack lignin peroxidase. Instead, many produce laccase, even though the redox potentials of known laccases are too low to directly oxidize the non-phenolic components of lignin. Pycnoporus cinnabarinus is one example of a laccase-producing fungus that degrades lignin very efficiently. To overcome the redox potential barrier, P. cinnabarinus produces a metabolite, 3-hydroxyanthranilate that can mediate the oxidation of how non-phenolic substrates by laccase. This is the first description of how laccase might function in a biological system for the complete depolymerization of lignin.
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PMID:A fungal metabolite mediates degradation of non-phenolic lignin structures and synthetic lignin by laccase. 870 3

The white rot fungus Pycnoporus cinnabarinus was characterized with respect to its set of extracellular phenoloxidases. Laccase was produced as the predominant extracellular phenoloxidase in conjunction with low amounts of an unusual peroxidase. Neither lignin peroxidase nor manganese peroxidase was detected. Laccase was produced constitutively during primary metabolism. Addition of the most effective inducer, 2,5-xylidine, enhanced laccase production ninefold without altering the isoenzyme pattern of the enzyme. Laccase purified to apparent homogeneity was a single polypeptide having a molecular mass of approximately 81,000 Da, as determined by calibrated gel filtration chromatography, and a carbohydrate content of 9%. The enzyme displayed an unusual behavior on isoelectric focusing gels; the activity was split into one major band (pI, 3.7) and several minor bands of decreasing intensity which appeared at regular, closely spaced intervals toward the alkaline end of the gel. Repeated electrophoresis of the major band under identical conditions produced the same pattern, suggesting that the laccase was secreted as a single acidic isoform with a pI of about 3.7 and that the multiband pattern was an artifact produced by electrophoresis. This appeared to be confirmed by N-terminal amino acid sequencing of the purified enzyme, which yielded a single sequence for the first 21 residues. Spectroscopic analysis indicated a typical laccase active site in the P. cinnabarinus enzyme since all three typical Cu(II)-type centers were identified. Substrate specificity and inhibitor studies also indicated the enzyme to be a typical fungal laccase. The N-terminal amino acid sequence of the P. cinnabarinus laccase showed close homology to the N-terminal sequences determined for laccases from Trametes versicolor, Coriolus hirsutus, and an unidentified basidiomycete, PM1. The principal features of the P. cinnabarinus enzyme system, a single predominant laccase and a lack of lignin- or manganese-type peroxidase, make this organism an interesting model for further studies of possible alternative pathways of lignin degradation by white rot fungi.
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PMID:The ligninolytic system of the white rot fungus Pycnoporus cinnabarinus: purification and characterization of the laccase. 891 75

The cytochemical localization of the phenol oxidases, laccase and peroxidase, has been studied in pro-lignifying and lignifying Coleus blumei stem sections using 4-methoxy-alpha-naphthol as substrate. The results illustrated that, for short incubation times, both pro-lignifying and lignifying Coleus sections showed H2O2-dependent phenol oxidase (peroxidase-like) activity in epidermal and vascular tissues, while no detectable H2O2-independent phenol oxidase (laccase-like) activity was found in Coleus tissues. For long incubation times, H2O2-independent phenol-oxidases can also be detected in these tissues, however, this is probably due to the partial capability of intercellular washing fluid Coleus peroxidase to oxidize 4-methoxy-alpha-naphthol in the absence of exogenously added H2O2. This illustrates not only the importance of the substrate used, but also the importance of the incubation time, in the cytochemical localization of phenol oxidizing enzymes.
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PMID:Cytochemical localization of phenol-oxidizing enzymes in lignifying Coleus blumei stems. 917 41

The ability of Phanerochaete chrysosporium, Trametes versicolor, Coriolopsis polyzona, and Pleurotus ostreatus growing in a mitogen-limited mineral medium (NMM) to degrade PCBs in a commercial, Delor 106 mixture at a concentration of 0.9 ppm was compared. The respective amount of PCBs removed from the fungal cultures within 3 weeks were 25, 50, 41 and 0%. The capacities of the individual fungal species to remove PCBs correlated to some extent with their capabilities of decolorization of NMM agar containing both Poly R-478 or Remazol Brilliant Blue R dyes. Enzyme estimations indicated that both high and relatively stable activities of Mn-dependent peroxidase, Mn-independent peroxidase, lignin peroxidase, and laccase characterized efficient PCB degraders.
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PMID:Removal of PCBs by various white rot fungi in liquid cultures. 934 Mar 10

Effect of various cultivation conditions and lignin preparations on the enzymes of ligninolytic enzyme complex of white-rot fungus Pleurotus floridae has been studied. The maximal Mn-peroxidase activity was revealed in the medium with low nitrogen content (1.2 mM); maximal values of cellobiose quinone oxidoreductase activity were observed in the media with high nitrogen content (7.2 mM); maximal values of laccase activity in the media with low content of glucose (2 g/l) during Pleurotus floridae cultivation in Kirk's stationary cultures have been shown. Employment of submerged cultivation under conditions of mycelium immobilization on polyurethane carriers allowed us to increase laccase activity twice as compared with cultivation in small stationary cultures, while had the crucial effect on the Mn-peroxidase activity. The selective effect of the studied lignin preparations on the components of ligninolytic complex and their isoenzymes has been stated. The dependence of laccase and Mn-peroxidase activities on high and low-molecular weight fractions balance in lignin preparations has been established.
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PMID:[Effect of lignin preparations and cultivation conditions on the ligninolytic complex of the fungus Pleurotus floridae, the wood white-rot pathogen]. 945 73

Panaeolus sphinctrinus, Panaeolus papilionaceus, and Coprinus friesii are described as producers of ligninolytic enzymes. P. papilionaceus and P. sphinctrinus both produced a laccase. In addition, P. sphinctrinus produced a manganese peroxidase. C. friesii secreted a laccase and two peroxidases similar to the peroxidase of Coprinus cinereus. The purified laccases and peroxidases were characterized by broad substrate specificities, significant enzyme activities at alkaline pH values, and remarkably high pH optima. The two peroxidases of C. friesii remained active at pH 7.0 and 60 degrees C for up to 60 min of incubation. The peroxidases were inhibited by sodium azide and ethylene glycol-bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), whereas the laccases were inhibited by sodium azide and N,N-diethyldithiocarbamic acid. As determined by native polyacrylamide gel electrophoresis and isoelectric focusing, all three fungi produced laccase isoenzymes.
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PMID:Characterization of laccases and peroxidases from wood-rotting fungi (family Coprinaceae). 957 23

Fourteen strains of white-rot basidiomycetes belonging to eight species of two genera (Inonotus and Pholiota) were tested for their ability to maintain the production of laccase, peroxidase and manganese-dependent peroxidase (enzymes involved in lignin biodegradation) after a short-time preservation in liquid nitrogen with different cryoprotectives (glycerol, dimethyl sulfoxide). No negative effect of cryopreservation or the used cryoprotective on production of the ligninolytic enzymes was found in the fungi tested.
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PMID:Activities of ligninolytic enzymes in some white-rot basidiomycete strains after recovering from cryopreservation in liquid nitrogen. 980 64

The peculiarities of lignocellulose biotransformation by white-rot fungi Pleurotus floridae and Phellinus igniarius during their solid-state fermentation of wastes of oil-bearing crops processing has been studied. The dynamics of oil-bearing crops processing wastes bioconversion has been studied. It has been marked that P. floridae utilized 20% cellulose and lignin during 9 weeks and 40% lignin and 30% cellulose during all period of fermentation (19 weeks). The fungus P. igniarius utilized mainly cellulose (40% cellulose and 24% lignin in 19 weeks). Lignin-degradative capacity of P. floridae (KL = 0.57) and P. igniarius (KL = 0.34) has been quantitatively estimated. The degradation of plant biopolimers corresponded to the production of ligninolytic (laccase, Mn(2+)-dependent peroxidase,) and cellulolytic (CMC-cellulase) enzymes. The component and isoenzyme content of ligninolytic enzyme complex of fungi Pleurotus floridae and Phellinus igniarius has been determined.
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PMID:[Biotransformation of lignocellulse by the fungi Pleurotus floridae (Fries) Kummer and Phellinus igniarius (Linnearus:Fries) Quelet--the pathogens of white rot in trees]. 984 43

A basidiomycetous fungus Flavodon flavus (Klotzsch) Ryvarden (strain 312), isolated from decaying sea grass from a coral lagoon off the west coast of India, mineralized nearly 24% of 14C-labeled synthetic lignin to 14CO2 in 24 days. When grown in low-nitrogen medium (2.4 mM N) this fungus produced three major classes of extracellular lignin-modifying enzymes (LMEs): manganese-dependent peroxidase (MNP), lignin peroxidase (LIP), and laccase. Low MNP and laccase activities were seen in high-nitrogen medium (24 mM N), but no LIP activity was seen. In media containing lignocellulosic substrates such as pine, poplar, or sugarcane bagasse as the sole source of carbon and nitrogen, relatively high MNP and moderate levels of laccases were seen, but LIP production either was not seen or was minimal. LME production was also seen in media prepared with artificial seawater. Fast protein liquid chromatography and isoelectric focusing resolved LMEs into four isozymes each of MNP and LIP, while laccase isozymes were resolved into two groups, one group containing seven isozymes (pIs 4 to 6) and the other group containing at least three isozymes (pIs < 3). The molecular masses of the different isozymes were 43 to 99 kDa for MNP, 40 and 41.5 kDa for LIP, and 43 and 99 kDa for laccase. F. flavus showed effective degradation of various dye pollutants in media prepared with or without artificial seawater. This is the first report on the production of all three major classes of LMEs by F. flavus and points to the bioremediation potential of this organism in terrestrial as well as marine environments.
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PMID:Lignin-modifying enzymes of flavodon flavus, a basidiomycete isolated from a coastal marine environment 1022 7


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