title: Direct electron transfer--a favorite electron route for cellobiose dehydrogenase (CDH) from Trametes villosa. Comparison with CDH from Phanerochaete chrysosporium.
abstract: This paper presents some functional differences as well as similarities observed when comparing the newly discovered cellobiose dehydrogenase (CDH) from Trametes villosa (T.v.) with the well-characterized one from Phanerochaete chrysosporium (P.c.). The enzymes were physically adsorbed on spectrographic graphite electrodes placed in an amperometric flow through cell connected to a flow system. In the case of T.v.-CDH-modified graphite electrodes, a high direct electron transfer (DET) current was registered at the polarized electrode in the presence of the enzyme substrate reflecting a very efficient internal electron transfer (IET) process between the reduced FAD-cofactor and the oxidized heme-cofactor. In the case of P.c.-CDH-modified graphite electrodes, the DET process is not as efficient, and the current will greatly increase in the presence of a mediator (mediated electron transfer, MET). As a consequence, when comparing the two types of enzyme-modified electrodes an inverted DET/MET ratio for T.v.-CDH is shown, in comparison with P.c.-CDH. The rates of the catalytic reaction were estimated to be comparable for both enzymes, by measuring the combined DET + MET currents. The inverted DET/MET ratio for T.v.-CDH-modified electrodes might suggest that probably there is a better docking between the two domains of this enzyme and that the linker region of P.c.-CDH might have an active role in modulating the rate of the IET (by changing the interdomain distance), with respect to pH. Based on the new properties of T.v.-CDH emphasized in the present study, an analytical application of a third-generation biosensor for lactose was recently published.
authors.affiliation: Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden.
authors.forename: Leonard
authors.initials: L
authors.lastname: Stoica
authors.forename: Tautgirdas
authors.initials: T
authors.lastname: Ruzgas
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
mesh_terms: D000327:Adsorption; D001487:Basidiomycota / Q000201:enzymology*; D015374:Biosensing Techniques; D002237:Carbohydrate Dehydrogenases / Q000737:chemistry*; D004583:Electrons; D006108:Graphite / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D020075:Phanerochaete / Q000201:enzymology*; D012680:Sensitivity and Specificity; D013499:Surface Properties
chemical_list: D006108:Graphite; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase