Tryptophan Repressor-Binding Proteins from Escherichia coli and Archaeoglobus fulgidus as New Catalysts for 1,4-Dihydronicotinamide Adenine Dinucleotide-Dependent Amperometric Biosensors and Biofuel Cells

Zafar, Muhammad Nadeem; Tasca, Federico; Gorton, Lo; Patridge, Eric V.; Ferry, James G.; Noll, Gilbert


The tryptophan (W) repressor-binding proteins (WrbA) from Echerichia coli (EcWrbA) and Archaeoglobus fulgidus (AfWrbA) were investigated for possible use in 1,4-dihydronicotinamide adenine dinucleotide (NADH) dependent amperometric biosensors and biofuel cells. EcWrbA and AfWrbA are oligomeric flavoproteins binding one flavin mononucleotide (FMN) per monomer and belonging to a new family of NAD(P)H:quinone oxidoreductases (NQOs). The enzymes were covalently linked to a low potential Os redox polymer onto graphite in the presence of single-walled carbon nanotube (SWCNT) preparations of varying average lengths. The performance of the enzyme modified electrodes for NADH oxidation was strongly depending on the average length of the applied SWCNTs. By blending the Os redox polymer with SWCNTs, the electrocatalytic current could be increased up to a factor of 5. Results obtained for AfWrbA modified electrodes were better than those for EcWrbA. For NADH detection, a linear range between 5 mu M and 1 mM, a lower limit of detection of 3 mu M, and a sensitivity of 56.5 nA mu M-1 cm(-2) could be reached. Additionally spectro-electrochemical measurements were carried out in order to determine the midpoint potentials of the enzymes (-115 mV vs, NHE for EcWrbA and -100 mV vs NHE for AfWrbA pH 7.0). Furthermore, an AfWrbA modified electrode was used as an anode in combination with a Pt black cathode as a biofuel cell prototype.

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Título según WOS: ID WOS:000266095100050 Not found in local WOS DB
Título de la Revista: ANALYTICAL CHEMISTRY
Volumen: 81
Número: 10
Fecha de publicación: 2009
Página de inicio: 4082
Página final: 4088


Notas: ISI