FIG. 4.
c-type cytochromes detected in various R. sphaeroides mutants. Membrane fragments of various mutants were analyzed by SDS-PAGE, and c-type cytochromes were revealed via their peroxidase activities using TMBZ as described in Materials and Methods. c1+cp, co, cy, and c2 correspond to the cyt c1 and cp subunits of the cyt bc1 complex and the cbb3-Cox, cyt co subunit of the cbb3-Cox, membrane-attached electron carrier cyt cy, and soluble electron carrier cyt c2, respectively. Additional unidentified c-type cytochromes running behind the doublet corresponding to cyt cp+c1 are also visible.