title: Investigation of the mediated electron transfer mechanism of cellobiose dehydrogenase at cytochrome c-modified gold electrodes.
abstract: The present study reports on the comparison of direct and mediated electron transfer pathways in the interaction of the fungal enzyme cellobiose dehydrogenase (CDH) with the redox protein cytochrome c (cyt c) immobilised at a modified gold electrode surface. Two types of CDHs were chosen for this investigation: a basidiomycete (white rot) CDH from Trametes villosa and a recently discovered ascomycete from the thermophilic fungus Corynascus thermophilus. The choice was based on the pH-dependent interaction of these enzymes with cyt c in solution containing the substrate cellobiose (CB). Both enzymes show rather similar catalytic behaviour at lower pH, dominated by a direct electron exchange with the electrode. With increasing pH, however, also cyt c-mediated electron transfer becomes possible. The pH-dependent behaviour in the presence and in the absence of cyt c is analysed and the potential reaction mechanism for the two enzymes with a different pH-behaviour is discussed.
authors.affiliation: Biosystems Technology, Wildau Technical University of Applied Sciences, Wildau, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Sarauli
authors.forename: Roland
authors.initials: R
authors.lastname: Ludwig
authors.forename: Dietmar
authors.initials: D
authors.lastname: Haltrich
authors.forename: Lo
authors.initials: L
authors.lastname: Gorton
authors.forename: Fred
authors.initials: F
authors.lastname: Lisdat
mesh_terms: D001203:Ascomycota / Q000737:chemistry* / Q000201:enzymology; D055162:Biocatalysis; D002237:Carbohydrate Dehydrogenases / Q000737:chemistry* / Q000378:metabolism; D002475:Cellobiose / Q000737:chemistry / Q000378:metabolism; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D055664:Electrochemical Techniques; D004566:Electrodes; D004579:Electron Transport; D004583:Electrons; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D006046:Gold; D006863:Hydrogen-Ion Concentration; D055767:Immobilized Proteins / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D055454:Trametes / Q000737:chemistry* / Q000201:enzymology
chemical_list: D005656:Fungal Proteins; D055767:Immobilized Proteins; D002475:Cellobiose; D006046:Gold; D045304:Cytochromes c; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase