title: The magnetic susceptibility of reduced cytochrome P-450-cam.
abstract: The primary electron acceptor of Photosystem II has a midpoint oxidation-reduction potential of +95 mV at pH 7.0 in Photosystem II chloroplast fragments prepared by digitonin treatment. The midpoint potential of the acceptor has a pH dependence of -60 mV/pH unit. At concentrations that inhibit oxygen evolution, o-phenanthroline shifts the midpoint potential of the primary acceptor by +70 mV. The shifted potential retains the same dependence on pH. The effect of o-phenanthroline suggests that it interacts directly with the primary electron acceptor of Photosystem II in a manner similar to that reported previously for the primary electron acceptor in purple photosynthetic bacteria.
mesh_terms: D001665:Binding Sites; D002164:Camphor; D003201:Computers; D003577:Cytochrome P-450 Enzyme System; D008280:Magnetics; D008433:Mathematics; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D011549:Pseudomonas / Q000201:enzymology; D013696:Temperature; D013816:Thermodynamics
chemical_list: D002164:Camphor; D003577:Cytochrome P-450 Enzyme System