Electrochemical Activation of the Natural Catalytic Cycle of Cytochrome P450s in Human Liver Microsomes

Authors

  • Dhanuka P. Wasalathanthri,

    1. Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
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  • Spundana Malla,

    1. Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
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  • Ronaldo C. Faria,

    1. Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
    2. Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP, Brazil
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  • James F. Rusling

    Corresponding author
    1. Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
    2. National University of Ireland at Galway, Ireland
    3. Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, USA
    • Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
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Abstract

The natural catalytic cycle of cytochrome (cyt) P450 enzymes in human liver microsome (HLM) films was activated electrochemically via the electron transfer sequence electrode→cyt P450 reductase (CPR)→cyt P450. Cyclic voltammograms for HLM films had midpoint potentials of −0.50 V vs. SCE at pH 7.4 characteristic of CPR, not cyt P450s. HLM and CPR microsomes without cyt P450s did not electrocatalytically reduce H2O2, and did not shift midpoint potential when CO was added, also indicating that the peaks do not correspond to iron heme cyt P450 enzymes. Electrochemical activation of the natural cyt P450 cycle for substrate conversion via CPR in HLM films was confirmed by catalytic electrolysis in an electrochemical microfluidic array designed to generate and detect reactive metabolites by measuring their reactivity with DNA.

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