Electrochemistry of immobilized CuZnSOD and FeSOD and their interaction with superoxide radicals.
Copper, zinc superoxide dismutase (CuZnSOD) from bovine erythrocytes and iron superoxide dismutase from Escherichia coli (FeSOD) were immobilized on 3-mercaptopropionic acid (MPA)-modified gold electrodes, respectively. The characterization of the SOD electrodes showed a quasi-reversible, electrochemical redox behavior with a formal potential of 47+/-4 mV and -154+/-5 mV (vs. Ag/AgCl, 1 M KCl) for surface adsorbed CuZnSOD and FeSOD, respectively. The heterogeneous electron transfer rate constants were determined to be about 65 and 35/s, respectively. Covalent fixation of both SODs was also feasible with only slight changes in the formal potential. The interaction of superoxide radicals (O(2)(-)) with the SOD electrode was investigated. No catalytic current could be observed. However, due to the fast cyclic redox reaction of SOD with superoxide, the communication of the protein with the electrode was strongly influenced. The amperometric detection of superoxide radicals is discussed.
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Analytical Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Building 25, 14476 Golm, Germany.
Scheller
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FW
Lisdat
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D000327:Adsorption; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized; D004912:Erythrocytes / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry; D006046:Gold; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000145:classification; D013481:Superoxides / Q000032:analysis* / Q000737:chemistry*
D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D013481:Superoxides; D006046:Gold; D013482:Superoxide Dismutase