title: Reconstitution of apo-glucose dehydrogenase on pyrroloquinoline quinone-functionalized au nanoparticles yields an electrically contacted biocatalyst.
abstract: An electrically contacted glucose dehydrogenase (GDH) enzyme electrode is fabricated by the reconstitution of the apo-GDH on pyrroloquinoline quinone (PQQ)-functionalized Au nanoparticles (Au-NPs), 1.4 nm, associated with a Au electrode. The Au-NPs functionalized with a single amine group were attached to the Au surface by 1,4-benzenedithiol bridges, and PQQ was covalently linked to the Au-NPs. The apo-GDH was then reconstituted on the PQQ cofactor sites. The surface coverage of GDH corresponded to 1.4 x 10(-12) mol cm(-2). The reconstituted enzyme revealed direct electrical contact with the electrode surface, and the bioelectrocatalytic oxidation of glucose occurred with a turnover number of 11,800 s(-1). In contrast, a system that included the covalent attachment of GDH to the PQQ-Au-NPs monolayer in a random, nonaligned, configuration revealed lack of electrical communication between the enzyme and the electrode, albeit the enzyme existed in a bioactive structure. The bioelectrocatalytic function of the later system was, however, activated by the diffusional electron mediator 2,6-dichlorophenol-indophenol. The results imply that the alignment of GDH on a Au-NP through the reconstitution process leads to an electrically contacted enzyme-electrode, where the Au-NP acts as a charge-transfer mediator.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Zayats
authors.forename: Eugenii
authors.initials: E
authors.lastname: Katz
authors.forename: Ronan
authors.initials: R
authors.lastname: Baron
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D015086:2,6-Dichloroindophenol / Q000737:chemistry; D001051:Apoenzymes / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods; D002384:Catalysis; D004563:Electrochemistry; D004566:Electrodes; D004789:Enzyme Activation; D042843:Glucose 1-Dehydrogenase / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D036103:Nanotechnology; D045542:PQQ Cofactor / Q000737:chemistry*; D010316:Particle Size
chemical_list: D001051:Apoenzymes; D045542:PQQ Cofactor; D006046:Gold; D015086:2,6-Dichloroindophenol; D042843:Glucose 1-Dehydrogenase