Redox potential of the cytochrome c in the flavocytochrome p-cresol methylhydroxylase

The redox potential of the cytochrome c in 5 flavocytochrome c proteins, all p-cresol methylhydroxylases purified from species of Pseudomonas, was measured. All gave similar values ranging from 226-250 mV. Two of the enzymes, from Pseudomonas putida NC1B 9866 and NC1B 9869, were resolved into their flavoprotein and cytochrome subunits and the redox potentials of the isolated cytochrome c subunits measured. The values for these were 60-70 mV below those for the whole enzymes but, in both cases, reconstitution of active enzyme by addition of the flavoprotein subunit restored the original potential.