Abstract
We have tried to measure precisely the redox potential of the primary electron donor of photosystem (PS) I, P700, with a spectroelectrochemical technique. Then, we have succeeded to determine the P700 redox potential, and also have found for the first time the species-dependence of the P700 redox potential. In the present study, we investigate the spectroscopic properties of P700 to elucidate the factors for the species-dependence. The differences in absorbance and circular dichroism (CD) of P700+ - P700 of cyanobacteria, red and green algae, and higher plants were different from species to species. The spectroscopic results will be discussed with the species-dependence of the P700 redox potential.
