Direct electrochemistry of photosystem I

Direct electrochemistry has been developed into a powerful tool for the analysis of soluble proteins and enzymes over the past two decades. In the present study, we have expanded the range of proteins to include a solubilized membrane protein, photosystem I. Taking into account the difficulties caused by the presence of detergent, we have shown it to be possible to obtain an electrochemical signal of the primary electron donor, a chlorophyll dimer called P700, of photosystem I. A reduction potential of E1/2=490 mV vs. SHE with a peak separation of ΔE=100 mV was found, in good agreement with literature values.