title: Kinetic and biochemical properties of high and low redox potential laccases from fungal and plant origin.
abstract: The electrochemical studies of laccase-mediator systems are aimed at understanding the mechanism of their redox transformation and their efficiency in both homogeneous and heterogeneous reactions; this topic has paramount application spanning from bleaching of paper pulp and the enzymatic degradation of lignin to the biosensors and biofuel cell development. In this paper four different laccases from Trametes hirsuta (ThL), Trametes versicolor (TvL), Melanocarpus albomyces (r-MaL) and Rhus vernicifera (RvL) were characterized from both biochemical and electrochemical points of view. Two of them (TvL and ThL) are high redox potential and two (RvL and r-MaL) are low redox potential laccases. The outline of this work is focused on the determination of catalytic and bioelectrochemical properties of these four enzymes in homogenous solution as well as immobilized onto electrode surface in the presence of a set of different redox mediators. The results measured in the homogenous reaction system correlated well with those measured with the immobilized enzymes. In addition, they are in good agreement with those reported with reference techniques, suggesting that the electrochemical methods employed in this work can be applied well in place of the traditional techniques commonly used for the kinetic characterization of laccases. These results are also discussed in terms of the known amino acid sequences and three-dimensional (3D) structures of the laccases.
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, 00185 Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Frasconi
authors.forename: Gabriele
authors.initials: G
authors.lastname: Favero
authors.forename: Harry
authors.initials: H
authors.lastname: Boer
authors.forename: Anu
authors.initials: A
authors.lastname: Koivula
authors.forename: Franco
authors.initials: F
authors.lastname: Mazzei
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D055664:Electrochemical Techniques; D004800:Enzymes, Immobilized; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D042845:Laccase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029045:Rhus / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D020037:Sordariales / Q000201:enzymology / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D055454:Trametes / Q000201:enzymology / Q000235:genetics
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D010940:Plant Proteins; D042845:Laccase