Electrochemical characterization of synthetic metalloenzymes

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Aim of this project is focused on establishing the relationship between electron transfer
properties and catalytic activities of selected artificial metalloenzymes. These hybrid
biomacromolecules were designed by French partners by covalent anchoring of new
catalytically-active metal complexes within the active site of a selected protein host to achieve
asymmetric catalysis in aqueous media. Catalytic cycle involves transfer of two electrons and
thus electrochemical methods can provide new insights into the mechanism of the catalytic
process. Namely, catalytic hydrogen evolution is the targeted electrochemical process at the
electrode-electrolyte interface in the aqueous solution. This process will be explored using the
protein host before and after covalent linking of the organometallic fragments. Cyclic
voltammetry, spectroelectrochemistry, chronopotentiometric stripping analysis (H-peak) and
phase sensitive electrochemical methods including electrochemical impedance spectroscopy
will be used. Ultimately, we aim at addressing the electron transfer mechanism issues. Two
types of approaches will be used. First one is the classical transfer of electrons from electrode
to redox active site of the biomolecule and second one involves transport of charge in the
electrode-metalloenzyme-electrode junctions. In both cases current as a function of applied
voltage is obtained. In the second case Czech partners will use their unique instrumentation
that allows measurements of very low currents and the current voltage characteristics in the
statistically significant number of two electrode junctions. From such experiments one can
obtain conductance value corresponding to a single metalloenzyme molecule. Single molecule
conductance studies will aim at evaluation of these artificial biopolymers as possible building
blocks of molecular bioelectronic devices.
Results will be published in international journals and participation of students is expected for
further strengthening of the cooperation.

Mgr. HROMADOVÁ Magdaléna Ph.D.