Fungal laccase

Laccase, 6,699 copper, 6,654 cytochrome oxidases concerted electron transfer, 6,683 fungal... 

C13-0112. Fungal laccase is an enzyme found in fungi that live on rotting wood. The enzyme is blue and contains 0.40% by mass copper. The molar mass of the enzyme is approximately 64,000 g/mol. How many copper atoms are there in one molecule of fungal laccase ... 

Cho, N.S., Rogalski, J., Jaszek, M., Luterek, J., Wojtas-Wasilewska, M., Malarczyk, E., Fink-Boots, M., and Leonowicz, A., Effect of coniferyl alcohol addition on removal of chlorophenols from water effluent by fungal laccase, J. Wood Sci., 45, 174-178, 1999. 

Fungal laccases (benzenediokoxygen oxidoreductase, EC 1.10.3.2) belong to the multicopper blue phenoloxidases. They comprise glycosylated proteins expressed in multiple forms and variable molecular weight, ranging from 59 to 110 kDa. Laccase is expressed as multiple constitutive and induced isoenzymes [30, 64]. The enzyme contains four copper atoms (Cu), in different states of oxidation (I, II, III) [65], which play an important role in the catalytic mechanism. Laccase oxidizes different compounds while reducing O2 to H20, a total reduction of four electrons. 

Malmstrom, B.G., Mosbach, R., and Vanngard, T. 1959. An electron spin resonance study of the state of copper in fungal laccase. Nature 183 321-322. 

Laccase was first isolated by Yoshida in 1883 [43] from tree lacquer of Rhus ver-nicifera. Laccases can thus be classified according to their source plant, fungal or, more recently, bacterial or insect [44], The laccase enzyme active site contains four copper ions classified into three types based upon their geometry and coordinating ligands, denoted... 

Co-immobilization of this redox polymer with a fungal laccase from Trametes versicolor, possessing a Tl copper site reduction potential of +0.57 V vs Ag/AgCl ( +0.77 vs NHE), was achieved using a diepoxide cross-linker, in an approach... 

Gianfreda L, Sannino F, Filazzola MT, Leonowicz A (1998) Catalytic behavior and detoxifying ability of a laccase from the fungal strain Cerrena unicolor. J Mol CatBEnz 14 13-23... 

The laccase molecule is a dimeric or tetrameric glycoprotein, which contains four copper atoms per monomer, distributed in three redox sites. More than 100 types of laccase have been characterized. These enzymes are glycoproteins with molecular weights of 50-130 kDa. Approximately 45% of the molecular weight of this enzyme in plants are carbohydrate portions, whereas fungal laccases contain less of a carbohydrate portion (10-30%). Some studies have suggested that the carbohydrate portion of the molecule ensures the conformational stability of the globule and protects it from proteolysis and inactivation by radicals (Morozova and others 2007). 

Thurston CF. 1994. The structure and function of fungal laccases. Microbiology 140(1) 19—26. 

Claus H, Faber G, Koenig H (2002) Redox-mediated decolorization of synthetic dyes by fungal laccases. Appl Microbiol Biotechnol 59 672-678... 

Hofer C, Schlosser D (2000) Novel enzymatic oxidation of Mn+2 to Mn+3 catalyzed by a fungal laccase. FEBS 451 186-190... 

Susla M, Novotny C, Svobodova K (2007) The implication of Dichomitus squalens laccase isoenzymes in dye decolorization by immobilized fungal cultures. Bioresour Technol 98 2109-2115... 

Table 5.2 contains data about selected copper enzymes from the references noted. It should be understood that enzymes from different sources—that is, azurin from Alcaligenes denitrificans versus Pseudomonas aeruginosa, fungal versus tree laccase, or arthropodan versus molluscan hemocyanin—will differ from each other to various degrees. Azurins have similar tertiary structures—in contrast to arthropodan and molluscan hemocyanins, whose tertiary and quaternary structures show large deviations. Most copper enzymes contain one type of copper center, but laccase, ascorbate oxidase, and ceruloplasmin contain Type I, Type II, and Type III centers. For a more complete and specific listing of copper enzyme properties, see, for instance, the review article by Solomon et al.4... 

Nicole et al. (71) Rigidoporus lignosus Fungal sheaths had a dense or loose fibrillar appearance close association between extracellular fibrils and wood cell walls was observed in both early and advanced stages of wood alteration galactose residues and laccase present in the sheath... 

Scheme 29. Oxidative decarboxylation of tetrahydroisoquinoline-1-carboxylic acids by fungal laccase and horseradish peroxidase.

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