Doctoral researcher: Karuppasamy Dharmaraj
Principle investigator: Fritz Scholz
Co-supervisors: U. Lendeckel, C. Stöhr
The study of charge transfer reactions of redox systems in monolayers of mitochondrial membranes
Previous experiments have shown that mitochondria disintegrate on a mercury electrode to form islands of adsorbed lipids, including other membrane constituents. These measurements have been performed to study the fluidity of the mitochondrial membranes.
Preliminary experiments have shown that electrodes covered with complete monolayers of disintegrated mitochondria give very pronounced redox signals in voltammetric measurements (see Figure), which are obviously caused by redox active constituents of the mitochondria.
The central idea of this project is to prepare monolayers of disintegrated mitochondria on electrodes, and to study the charge transfer reactions of the incorporated redox active systems.
In a first stage, model monolayers of lipids (including cardiolipins) with various ubiquinones, vitamin K, carotenes and redox enzymes will be studied to elucidate the effect of lipid layers on the thermodynamics and kinetics of the redox systems.
In the second stage, mitochiondria from the group of Lendeckel and membrane vesicles from the group of Stöhr will be studied and the results will be correlated with physiological parameters.
There are previous and rather recent publications in which the electrochemical detection of signals of redox active components of mitochondrial membranes have been attempted, however, the measurements were performed at rather badly characterized solid electrodes, where no simple monolayers of the mitochondrial membranes are formed, so that the interpretation of the experiments is not straight forward. In our experiments, we expect to obtain much more meaningful data.
 Hermes M., Scholz F., Härdtner C., Walther R., Schild L., Wolke C., Lendeckel U.: Angew. Chem. Int. Ed. (2011) 50, 6872–6875.
 Heise N., Gürtler S., Lendeckel U., Scholz F.: manuscript in preparation
 Wang T., Minteer Sh.D.: J. Electrochem. Soc. (2016) 163, H1047-H1052.
University of Greifswald