Procedures and conditions for application of the pyridine hemochrome method to photosynthetically grown cells of Rhodopseudomonas sphaeroides. 
The conditions and pretreatments required in the conventional pyridine hemochrome method were re-examined for application of the method to the measurement of protoheme and heme c contents in photosynthetically grown cells of Rhodopseudomonas sphaeroides.  The amounts of hemes were calculated from two kinds of difference absorbances between two wavelengths of the redox difference spectrum of the pyridine hemochromes prepared from the disrupted cells.  Extraction of photosynthetic pigments from the cells with organic solvents and separation of hemes in hemoproteins into the protoheme and the heme c fractions by the differential extraction of hemes with an acidified organic solvent were omitted.