Redox potential of plastoquinone A in spinach chloroplasts.
The redox potential of plastoquinone A in spinach chloroplasts was determined. The midpoint potential of the quinone is about +80 mV at pH 7.0 with an n value of 2. The pH-dependence of the potential is -30 mV per pH between pH 4.0 and 5.7, and -60 mV per pH between pH 5.7 and 8.0. The change of the slope at pH 5.7 is interpreted as the protonation of the oxidized plastoquinone A.
D001894:Borohydrides / Q000494:pharmacology; D002736:Chloroplasts / Q000378:metabolism*; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008433:Mathematics; D010084:Oxidation-Reduction; D010944:Plants; D010971:Plastoquinone / Q000378:metabolism*; D011809:Quinones / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
D001894:Borohydrides; D011809:Quinones; D010971:Plastoquinone