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)

Laccase (p-diphenol:oxygen oxidoreductase; EC 1.10.3.2) from Neurospora crassa has been immobilized by two different procedures: (1) Covalent attachment to Sepharose 4B activated with cyanogen bromide, and (2) Adsorption to Concanavalin A-Sepharose via the carbohydrate moiety. Except for small changes in the Michaelis-Menten constants, no differences were noted in the enzymological properties of the immobilized enzymes when compared to free enzyme. The carbohydrate moiety of laccase involved in the interaction with Concanavalin A does not appear to be closely associated with the active center since binding to the lectin has no effect on the enzymological parameters investigated.
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PMID:Properties of the glycoprotein laccase immobilized by two methods. 24 72

In a diverse taxonomic range of tree species, including representative species of ancient families of angiosperms (Magnolia x soulangiana Soul.-Bod.) and gymnosperms (Ginkgo biloba L.), oxidase activity was associated with cell walls of developing xylem and was enriched in extracts of cell wall-associated glycoproteins. In all species where oxidase activity was detected histochemically, it was expressed in cell walls of lignifying, differentiating xylem cells and was absent from old wood, cambium and phloem, suggesting that oxidases have a conservative role in lignification of tree xylem. An oxidase from the developing xylem of Picea sitchensis (Bong) Carr. (Sitka spruce) was partially purified by a combination of lectin affinity and immobilized metal ion affinity chromatography. A portion of the total oxidase activity had high affinity for immobilized zinc ions and this feature allowed it to be separated from the bulk of oxidase activity. Two polypeptides that could have been responsible for the bound oxidase activity were enriched by this procedure. The smaller polypeptide of Mr approximately 73 kDa yielded an N-terminal amino-acid sequence that was homologous to laccase-like polyphenol oxidases (E.C. 1.10.3.2) from loblolly pine (Pinus taeda L.), poplar (Populus euramericana (Dode) Guinier) and Arabidopsis. The larger polypeptide (Mr approximately 77 kDa) yielded an N-terminal amino-acid sequence that was homologous with a range of plant subtilisin-like serine proteinases. The roles of oxidase and proteinase activities in developing xylem are discussed.
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PMID:Oxidase activity in lignifying xylem of a taxonomically diverse range of trees: identification of a conifer laccase. 1130 58

In order to find immune-relevant factors responsible for virus resistance and response to the virus infection, the suppression subtractive hybridisation method was employed to identify differentially expressed genes and their expression profiles in the hepatopancreas of the white spot syndrome virus (WSSV) resistant and susceptible Pacific white shrimp (Litopenaeus vannamei). Two forward subtractive libraries (at 0 and 48h time point) and two reverse subtractive libraries (at 0 and 48h time point) were constructed, and more than 1200 clones were sequenced, of which 40 differentially expressed genes were identified. These genes encode proteins corresponding to a wide range of functions, including defence-related proteins, enzymes, transcription factors, apoptotic-related proteins, intracellular components potentially related to signaling cascades, metabolic proteins, and cytoskeletal protein. Five genes (laccase, carboxypeptidase B, H(+)-transporting ATP synthase, Acyl-ConA-binding protein (ACBP), and cortical granule protein with LDL-receptor) are found for the first time in shrimp and their expressions were up-regulated in the virus-resistant shrimp. Among the 40 genes, 30 showed up-regulation in the virus-resistant shrimp comparing with susceptible shrimp, while 10 genes showed down-regulation. Haemocyanin was the most abundant gene in our forward subtractive libraries. In addition, chathepsin L, ecdysteroid regulated protein, zinc proteinase, lectin, sterol carrier protein-X, lysozyme, cortical granule protein with LDL-receptor, leucine-rich repeat LGI family, fatty acid binding protein, and preamylase all showed up-regulation in the resistant shrimp. Furthermore, a number of genes encoding apoptotic-related proteins and antioxidant enzymes were expressed at a higher level in the virus-resistant shrimp. The high expression of the immune-relevant genes in response to the virus infection provides a new insight for further study in the shrimp innate immunity.
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PMID:Profiling of differentially expressed genes in hepatopancreas of white spot syndrome virus-resistant shrimp (Litopenaeus vannamei) by suppression subtractive hybridisation. 1715 65

Amorphous cellulose was used as a specific carrier for the deposition of self-assembled multienzyme complexes capable of catalyzing coupled reactions. Naturally glycosylated fungal cellobiohydrolases (CBHs) of glycosyl hydrolase families 6 and 7 were specifically deposited onto the cellulose surface through their family I cellulose-binding modules (CBM). Naturally glycosylated fungal laccase was then deposited onto the preformed glycoprotein layer pretreated by ConA, through the interaction of mannosyl moieties of fungal glycoproteins with the multivalent lectin. The formation of a cellulase-ConA-laccase composite was proven by direct and indirect determination of activity of immobilized laccase. In the absence of cellulases and ConA, no laccase deposition onto the cellulose surface was observed. Finally, basidiomycetous cellobiose dehydrogenase (CDH) was deposited onto the cellulose surface through the specific interaction of its FAD domain with cellulose. The obtained paste was applied onto the surface of a Clark-type oxygen electrode and covered with a dialysis membrane. In the presence of traces of catechol or dopamine as mediators, the obtained immobilized multienzyme composite was capable of the coupled oxidation of cellulose by dissolved oxygen, thus providing the basis for a sensitive assay of the mediator. Swollen amorphous cellulose plays three different roles in the obtained biosensor as: (i) a gelforming matrix that captures the analyte and its oxidized intermediate, (ii) a specific carrier for protein self-assembly, and (iii) a source of excess substrate for a pseudo-reagent-less assay with signal amplification. The detection limit of such a tri-enzyme biosensor is 50-100 nM dopamine.
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PMID:Application of cellulose-based self-assembled tri-enzyme system in a pseudo-reagent-less biosensor for biogenic catecholamine detection. 1737 47

Commercial mushroom tyrosinase contains other proteins, enzymes, carbohydrates, and phenolic material besides tyrosinase. Carbohydrate and phenolic material comprise a large percentage of the powder resuspensions derived from Agaricus bisporus. Enzyme assays identified the presence of tyrosinase, laccase, beta-glucosidase, beta-galactosidase, beta-xylosidase, cellulase, chitinase, xylanase, and mannanase in the commercial tyrosinase. Protein sequencing indicated the presence of tyrosinase, a lectin, and a putative mannanase as well as 10 unidentified protein/peptides in the commercial tyrosinase preparations. Characteristics of tyrosinase isoforms were similar in two different commercial tyrosinase sources. Inhibition studies indicated that I 50 values for some tyrosinase inhibitors were different when the crude powder was compared to a partially purified tyrosinase. The presence of these contaminants has the potential to affect studies using commercial tyrosinase.
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PMID:Enzyme, protein, carbohydrate, and phenolic contaminants in commercial tyrosinase preparations: potential problems affecting tyrosinase activity and inhibition studies. 1850 Aug 13

The white-rot fungus Lentinus edodes produced D-melibiose-specific lectins and two laccase forms in a lignin-containing medium. The maxima of laccase and lectin activities coincided, falling within the period of active mycelial growth. The enzymes and lectins were isolated and purified by gel filtration followed by anion-exchange chromatography. The L. edodes lectins were found to be able to stabilize the activity of the fungus's own laccases. Lectin activity during the formation of lectin-enzyme complexes remained unchanged.
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PMID:Laccase and lectin activities of intracellular proteins produced in a submerged culture of the xylotrophic basidiomycete Lentinus edodes. 1866 24

We show here, to our knowledge for the first time, that the brown mycelial mat of the xylotrophic shiitake medicinal mushroom, Lentinus edodes, not only performs a protective function owing to significant changes in the ultrastructure (thickening of the cell wall, increased density, and pigmentation of the fungal hyphae) but also is a metabolically active stage in the development of the mushroom. The cells of this morphological structure exhibit repeated activation of expression of the genes lcc4, tir, exp1, chi, and exg1, coding for laccase, tyrosinase, a specific transcription factor, chitinase, and glucanase, which are required for fungal growth and morphogenesis. This study revealed the maximum activity of functionally important proteins with phenol oxidase and lectin activities, and the emergence of additional laccases, tyrosinases, and lectins, which are typical of only this stage of morphogenesis and have a regulatory function in the development and formation of fruiting bodies.
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PMID:Brown Mycelial Mat as an Essential Morphological Structure of the Shiitake Medicinal Mushroom Lentinus edodes (Agaricomycetes). 2919 56