title: The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes.
abstract: It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials.Escherichia coliNrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2electrodes. CymA fromShewanella oneidensisMR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes.
authors.affiliation: School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom. ; School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Duncan G G
authors.initials: DG
authors.lastname: McMillan
authors.affiliation: Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
authors.forename: Sophie J
authors.initials: SJ
authors.lastname: Marritt
authors.affiliation: Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
authors.forename: Gemma L
authors.initials: GL
authors.lastname: Kemp
authors.affiliation: Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
authors.forename: Piers
authors.initials: P
authors.lastname: Gordon-Brown
authors.affiliation: Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
authors.forename: Julea N
authors.initials: JN
authors.lastname: Butt
authors.affiliation: School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom. ; School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Lars J C
authors.initials: LJ
authors.lastname: Jeuken
keywords: Self-assembled monolayer (SAM); cytochrome; lipid vesicle; protein-film electrochemistry (PFE); quinone