Abstract
A series of electron-transfer reaction is started by the charge separation in the reaction center (RC), which must be influenced by the redox potential of the environment. From this viewpoint, we controlled the redox potential of RC, chemically and electrochemically, and examined the changes in the electronic-absorption spectra of RC from Rba. sphaeroides R26.1. In the case of chemical control, we used “sodium ascorbate” as the oxidant and “dithionite” as the reductant. In the case of electrochemical control, we applied voltage to the RC suspension to which mediators, ferrocene and its derivatives, were added. When the voltage was high enough, the RC was oxidized; whereas in low, reduced. Now, we are trying to excite the special-pair bacteriochlorophyll in the RC, and to measure the sub-μs time-resolved absorption spectra.
