TY - JOUR A1 - Pinyou, Piyanut A1 - Ruff, Adrian A1 - Poeller, Sascha A1 - Alsaoub, Sabine A1 - Leimkühler, Silke A1 - Wollenberger, Ursula A1 - Schuhmann, Wolfgang T1 - Wiring of the aldehyde oxidoreductase PaoABC to electrode surfaces via entrapment in low potential phenothiazine-modified redox polymers JF - Bioelectrochemistry : an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry ; official journal of the Bioelectrochemical Society N2 - Phenothiazine-modified redox hydrogels were synthesized and used for the wiring of the aldehyde oxidoreductase PaoABC to electrode surfaces. The effects of the pH value and electrode surface modification on the biocatalytic activity of the layers were studied in the presence of vanillin as the substrate. The enzyme electrodes were successfully employed as bioanodes in vanillin/O-2 biofuel cells in combination with a high potential bilirubin oxidase biocathode. Open circuit voltages of around 700 mV could be obtained in a two compartment biofuel cell setup. Moreover, the use of a rather hydrophobic polymer with a high degree of crosslinking sites ensures the formation of stable polymer/enzyme films which were successfully used as bioanode in membrane-less biofuel cells. (C) 2015 Elsevier B.V. All rights reserved. KW - Aldehyde oxidoreductase KW - Enzyme electrode KW - Redox polymer KW - Phenothiazine KW - Biosensor KW - Biofuel cell Y1 - 2016 U6 - https://doi.org/10.1016/j.bioelechem.2015.12.005 SN - 1567-5394 SN - 1878-562X VL - 109 SP - 24 EP - 30 PB - Elsevier CY - Lausanne ER - TY - JOUR A1 - Badalyan, Artavazd A1 - Yoga, Etienne Galemou A1 - Schwuchow, Viola A1 - Pöller, Sascha A1 - Schuhmann, Wolfgang A1 - Leimkühler, Silke A1 - Wollenberger, Ursula T1 - Analysis of the interaction of the molybdenum hydroxylase PaoABC from Escherichia coli with positively and negatively charged metal complexes JF - Electrochemistry communications : an international journal dedicated to rapid publications in electrochemistry N2 - An unusual behavior of the periplasmic aldehyde oxidoreductase (PaoABC) from Escherichia coil has been observed from electrochemical investigations of the enzyme catalyzed oxidation of aromatic aldehydes with different mediators under different conditions of ionic strength. The enzyme has similarity to other molybdoenzymes of the xanthine oxidase family, but the catalytic behavior turned out to be very different. Under steady state conditions the turnover of PaoABC is maximal at pH 4 for the negatively charged ferricyanide and at pH 9 for a positively charged osmium complex. Stopped-flow kinetic measurements of the catalytic half reaction showed that oxidation of benzaldehyde proceeds also above pH 7. Thus, benzaldehyde oxidation can proceed under acidic and basic conditions using this enzyme, a property which has not been described before for molybdenum hydroxylases. It is also suggested that the electron transfer with artificial electron acceptors and PaoABC can proceed at different protein sites and depends on the nature of the electron acceptor in addition to the ionic strength. (C) 2013 Elsevier B.V. All rights reserved. KW - Electron transfer KW - Multi-cofactor enzymes KW - Molybdoenzymes KW - Aldehyde oxidoreductase Y1 - 2013 U6 - https://doi.org/10.1016/j.elecom.2013.09.017 SN - 1388-2481 SN - 1873-1902 VL - 37 SP - 5 EP - 7 PB - Elsevier CY - New York ER - TY - JOUR A1 - Badalyan, Artavazd A1 - Neumann-Schaal, Meina A1 - Leimkühler, Silke A1 - Wollenberger, Ursula T1 - A Biosensor for aromatic aldehydes comprising the mediator dependent PaoABC-Aldehyde oxidoreductase JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis N2 - A novel aldehyde oxidoreductase (PaoABC) from Escherichia coli was utilized for the development of an oxygen insensitive biosensor for benzaldehyde. The enzyme was immobilized in polyvinyl alcohol and currents were measured for aldehyde oxidation with different one and two electron mediators with the highest sensitivity for benzaldehyde in the presence of hexacyanoferrate(III). The benzaldehyde biosensor was optimized with respect to mediator concentration, enzyme loading and pH using potassium hexacyanoferrate(III). The linear measuring range is between 0.5200 mu M benzaldehyde. In correspondence with the substrate selectivity of the enzyme in solution the biosensor revealed a preference for aromatic aldehydes and less effective conversion of aliphatic aldehydes. The biosensor is oxygen independent, which is a particularly attractive feature for application. The biosensor can be applied to detect contaminations with benzaldehyde in solvents such as benzyl alcohol, where traces of benzaldehyde in benzyl alcohol down to 0.0042?% can be detected. KW - Aldehyde oxidoreductase KW - Benzaldehyde KW - Biosensor KW - Aromatic aldehydes KW - Molybdenum cofactor Y1 - 2013 U6 - https://doi.org/10.1002/elan.201200362 SN - 1040-0397 VL - 25 IS - 1 SP - 101 EP - 108 PB - Wiley-VCH CY - Weinheim ER -