ac010701u_si_001.pdf (103.35 kB)
Direct Voltammetry and Catalysis with Mycobacterium tuberculosis Catalase−Peroxidase, Peroxidases, and Catalase in Lipid Films
journal contribution
posted on 2001-11-30, 00:00 authored by Zhe Zhang, Salem Chouchane, Richard S. Magliozzo, James F. RuslingStable films of dimyristoylphosphatidylcholine and M.
tuberculosis catalase−peroxidase (KatG), several peroxidases, myoglobin, and catalase showed reversible FeIII/FeII voltammetry on pyrolytic graphite electrodes and
catalytic current for hydrogen peroxide and oxygen. Amperometric responses for these films to H2O2 at 0 V are
likely to contain significant contributions from catalytic
reduction of oxygen produced during the catalytic cycles.
Relative apparent turnover rates at pH 6 based on steady-state currents at 0 V versus SCE in the presence of H2O2
were in the order horseradish peroxidase > cytochrome
c peroxidase (CcP) > soybean peroxidase > myoglobin
> KatG > catalase. Lower currents for the very efficient
peroxide scavengers KatG and catalase may be related to
the instability of their compounds I in the presence of
H2O2. KatG catalyzed the electrochemical reduction of
oxygen more efficiently than catalase and CcP but less
efficiently than the other peroxidases. DMPC films incorporating glucose oxidase and peroxidases gave good
analytical responses to glucose, demonstrating the feasibility of dual enzyme−lipid films for biosensor fabrication.