Direct Voltammetry and Catalysis with Mycobacterium tuberculosis Catalase−Peroxidase, Peroxidases, and Catalase in Lipid Films

Abstract

Stable 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.

Third-Generation Biosensors Based on the Direct Electron Transfer of Proteins

“…DMPC films incorporating GOD and peroxidases have demonstrated good analytical responses to glucose. 130 That provides evidence for the feasibility of dual enzyme-lipid films for biosensor fabrication. Another bi-enzymatic biosensor was also constituted through a GOD-entrapping cellulose triacetate membrane, layered onto a polymeric membrane embedding HRP, which was previously blocked onto a pyrolitic graphite electrode.…”

Carbon Nanotubes as Suitable Electrochemical Platforms for Metalloprotein Sensors and Genosensors

“…Fe(II) has a very high affinity for oxygen and the latter process is immediately followed by a fast reaction of Protein-Fe(II) with oxygen. (Nakajima, 1987;Onuoha, 1997;Zhang, 2002).…”

“…The catalytic reduction of H 2 O 2 exhibits a behavior similar to the one found with oxygen, which suggests that the reaction mechanisms could be similar. Several plausible explanations have been provided in the literature (Nakajima, 1987;Onuoha, 1997;Zhang, 2002), under the assumption that H 2 O 2 can act as an oxidant or reductant agent. It has been suggested that H 2 O 2 reacts with MbFe(III) to give an oxyferryl radical ( • MbFe(IV)=O) which can react again with H 2 O 2 to produce oxygen and Mb(III).…”

Microbial P450 enzymes in biotechnology

“…P450cam which was immobilized on a glassy carbon electrode modified with sodium montmorillonite exhibited reversible redox behavior (Lei et al 2000). Direct electron transfer was reported for several oxygenases that were immobilized on lipid-modified pyrolytic graphite electrodes (Zhang et al 2002). A Co(III) sepulchrate mediator and Pt electrodes were able to transfer electrons to six different P450 monooxygenases (Estabrook et al 1996a;Estabrook et al 1996b;Estabrook et al 1996c).…”