Cytochrome c1 and b-type cytochrome with two heme centers in the photosynthetic membranes from Rhodopseudomonas palustris

Abstract

The photosynthetic membranes from Rhodopseudomonas palustris contained one species of membrane-bound c-type cytochrome, presumably cytochrome c 1, and a b-type cytochrome with two heme centers. The molecular weight and midpoint potential of cytochrome c 1 were 30000 and 275 mV, respectively. The α peak of the reduced-minus-oxidized difference spectrum of cytochrome c 1 was at 552 nm. Molecular weight of the b-type cytochrome was 32000 and the cytochrome had two midpoint potentials of 60 mV and −55 mV. The α peaks of the reduced-minus-oxidized difference spectra of the high and low midpoint potential heme centers were at 560 and 562 nm, respectively. These results suggested that there was a cytochrome b- c 1 complex in Rps. palustris.