TY  - JOUR
A1  - Badalyan, Artavazd
A1  - Dierich, Marlen
A1  - Stiba, Konstanze
A1  - Schwuchow, Viola
A1  - Leimkühler, Silke
A1  - Wollenberger, Ulla
T1  - Electrical wiring of the aldehyde oxidoreductase PaoABC with a polymer containing osmium redox centers
T2  - Biosensors
N2  - Biosensors for the detection of benzaldehyde and g-aminobutyric acid (GABA) are reported using aldehyde oxidoreductase PaoABC from Escherichia coli immobilized in a polymer containing bound low potential osmium redox complexes. The electrically connected enzyme already electrooxidizes benzaldehyde at potentials below −0.15 V (vs. Ag|AgCl, 1 M KCl). The pH-dependence of benzaldehyde oxidation can be strongly influenced by the ionic strength. The effect is similar with the soluble osmium redox complex and therefore indicates a clear electrostatic effect on the bioelectrocatalytic efficiency of PaoABC in the osmium containing redox polymer. At lower ionic strength, the pH-optimum is high and can be switched to low pH-values at high ionic strength. This offers biosensing at high and low pH-values. A “reagentless” biosensor has been formed with enzyme wired onto a screen-printed electrode in a flow cell device. The response time to addition of benzaldehyde is 30 s, and the measuring range is between 10–150 µM and the detection limit of 5 µM (signal to noise ratio 3:1) of benzaldehyde. The relative standard deviation in a series (n = 13) for 200 µM benzaldehyde is 1.9%. For the biosensor, a response to succinic semialdehyde was also identified. Based on this response and the ability to work at high pH a biosensor for GABA is proposed by coimmobilizing GABA-aminotransferase (GABA-T) and PaoABC in the osmium containing redox polymer.
KW  - redox polymer
KW  - aldehyde oxidoreductase
KW  - ionic strength
KW  - benzaldehyde
KW  - GABA
KW  - biosensor
Y1  - 2014
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/48851
VL  - 4
IS  - 4
SP  - 403
EP  - 421
PB  - MDPI
CY  - Basel
ER  -