title: Electron-transfer pathways between redox enzymes and electrode surfaces: reagentless biosensors based on thiol-monolayer-bound and polypyrrole-entrapped enzymes.
abstract: Based on previous results which showed that quinohemo-protein alcohol dehydrogenase (QH-ADH) entrapped within polypyrrole is able to directly transfer electrons via the conducting polymer to the electrode surface, the electron-transfer properties of this multi-cofactor enzyme adsorbed and covalently-bound to self-assembled thiol monolayers and bare electrode surfaces has been investigated more closely. While the dissolved enzyme is able to transfer electrons to the electrode via heme c as well as via the more deeply buried PQQ (fast adsorption-chemical reaction-desorption mechanism), an orientation of adsorbed QH-ADH on hydrophobic electrode surfaces, as well as of adsorbed and covalently bound QH-ADH on negatively-charged thiol monolayers could be observed. In these cases the heme c units are pointing towards the electrode surfaces resulting in an optimised direct ET rate.
authors.affiliation: Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, D-44780 Bochum, Germany. woschu@anachem.ruhr-uni-bochum.de
authors.forename: W
authors.initials: W
authors.lastname: Schuhmann
authors.forename: H
authors.initials: H
authors.lastname: Zimmermann
authors.forename: K
authors.initials: K
authors.lastname: Habermüller
authors.forename: V
authors.initials: V
authors.lastname: Laurinavicius
mesh_terms: D000426:Alcohol Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D015374:Biosensing Techniques; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D004800:Enzymes, Immobilized; D008567:Membranes, Artificial; D010088:Oxidoreductases / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D004800:Enzymes, Immobilized; D008567:Membranes, Artificial; D010088:Oxidoreductases; D000426:Alcohol Dehydrogenase