Matsuura K, Takamiya K, Itoh S, Nishimura M
J Biochem. 1980 May;87(5):1431-7. doi: 10.1093/oxfordjournals.jbchem.a132884.
The characteristics of the salt and pH dependences of the redox levels of cytochrome c2 and reaction center bacteriochlorophyll were studied in chromatophores from Rhodopseudomonas sphaeroides. They could be explained in terms of the difference of redox potential in the membrane from that in the bulk aqueous phase due to the electrostatic potential difference arising from charges fixed on the membrane surface. The midpoint potentials (Em) became lower when the surface potential (the electrostatic potential at the surface with reference to the bulk aqueous phase) had large negative values at lower salt concentrations at neutral pH, as predicted by the Gouy-Chapman theory. The rate of oxidation of cytochrome c2 in chromatophores by ferricyanide also depended on salt and pH levels. The rate was low at low salt concentrations, probably because of the lower surface concentration of ferricyanide compared with the bulk concentration, due to the surface potential.
研究了球形红假单胞菌的色素小体中细胞色素c2和反应中心细菌叶绿素氧化还原水平的盐依赖性和pH依赖性特征。这些特征可以用膜内氧化还原电位与本体水相中的氧化还原电位的差异来解释，这种差异是由于膜表面固定电荷产生的静电电位差所致。当中性pH下盐浓度较低时表面电位（相对于本体水相在表面的静电电位）具有较大的负值时，中点电位（Em）会降低，这正如古伊-查普曼理论所预测的那样。铁氰化物对色素小体中细胞色素c2的氧化速率也取决于盐和pH水平。在低盐浓度下该速率较低，可能是由于表面电位导致铁氰化物的表面浓度低于本体浓度。
