The Thermodynamic Characteristic of Four-Heme Cytochrome C from Rhodopseudomonas Viridis Reaction Centers

Abstract

Optical studies on Rps. viridis RCs provided evidence that all four hemes of cytochrome c have different absorption spectra in the α-band domain as well as midpoint potentials [1–4]. In this work we used the individual spectra of each heme and linear least-squares method to elucidate the quantity of every heme from full absorption spectra of cytochrome c in the α-band region as function of redox potential. For all four hemes the values of midpoint potentials established by the method of decomposition are in good agreement with those determined earlier [1].