[Purification and properties of cytochrome c552 from purple sulfur bacterium Thiocapsa roseopersicina].

The method of purification up to electrophoretical homogeneity of cytochrome c552 from the phototrophic bacterium Thiocapsa roseopersicina, strain BBS is described. For the cytochrome absorption spectrum the maxima at 417, 523 and 552 nm are characteristic for the reduced state and at 409 nm--for the oxidized state. The molecular weight is equal to 62000. The cytochrome contains two hemes per molecule and consists of two subunits. pI is 4.1; E0' is about 10 mV. Cytochrome c552 is a flavoprotein according to its fluorescence spectrum and subunit structure. T. roseopersicina cytochrome c552 is able to be reduced with sulphide, cysteine and ascorbate as well as with H2 in the presence of hydrogenase from the same bacterium. These data suggest that cytochrome c552 from T. roseopersicina functions in vivo at the initial stage of electron transport from hydrogen and sulphide.