Direct Heterogeneous Electron Transfer Reactions of Bacillus halodurans Bacterial Blue Multicopper Oxidase |
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| Authors: | Sergey Shleev Yan Wang Marina Gorbacheva Andreas Christenson Dietmar Haltrich Roland Ludwig Tautgirdas Ruzgas Lo Gorton |
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| Affiliation: | 1. Biomedical Laboratory Science, Health and Society, Malm? University, SE‐20506?Malm?, Sweden;2. Laboratory of Chemical Enzymology, A.?N. Bach Institute of Biochemistry, Russian Academy of Sciences 119071 Moscow, Russia;3. Department of Analytical Chemistry, Lund University, SE‐221 00 Lund, Sweden;4. Science Research Centre, Science Park, Harbin Institute of Technology, 150001 Harbin, P.?R. China;5. Department of Food Food Sciences and Technology, BOKU‐University of Natural Resources and Applied Life Sciences, A‐1190 Vienna, Austria |
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| Abstract: | Direct electron transfer reactions of Bacillus halodurans bacterial multicopper oxidase on bare spectrographic graphite, as well as bare and thiol‐modified gold electrodes were studied using cyclic voltammetry, potentiometry, amperometry, and spectroelectrochemistry. The redox potential of the T1 site of the enzyme was measured using mediatorless redox titration and found to be 325 mV±10 mV vs. NHE. From measurements with a mercaptopropionic acid‐modified gold electrode under aerobic conditions a midpoint potential of 360 mV vs. NHE for the T2/T3 copper cluster is deduced. Differing from most other characterized laccases of fungal and plant origins this bacterial enzyme exhibits bioelectrocatalytic activity at neutral pH and tolerates high chloride concentrations (200 mM), conditions that usually strongly inhibit catalysis. Moreover, it has the very high affinity towards molecular oxygen both in solution and in the adsorbed state (KM≤50 μM). |
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| Keywords: | Bacterial multicopper oxidase T1 site Redox potential Carbon Gold |
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