title: Subfractionation and characterization of soluble c-type cytochromes from Paracoccus denitrificans cultured under various limiting conditions in the chemostat.
abstract: Soluble c-type cytochromes were partially purified from Paracoccus denitrificans cells grown in succinate- and methanol-limited aerobic, nitrate-limited anaerobic and oxygen-limited chemostat cultures. Five c types could be distinguished with the following apparent molecular masses, absorption maxima and midpoint potentials. (a) 9.2 kDa, 549 nm and +190 mV; (b) 14 kDa, 549 nm and +227 mV; (c) 22 kDa, 552 nm and +190 mV; (d) 30 kDa, 552.7 nm and +160 mV; (e) 45 kDa, a dihaem: 555 nm, +128 mV and 551 nm, -163 mV. The 14-kDa polypeptide was present under all growth conditions examined and most probably is the already well characterized cytochrome c550. In methanol-limited grown cells three additional cytochromes were found, the 9.2-kDa, 22-kDa and 30-kDa ones. Under oxygen-limited conditions the 45-kDa and under anaerobic growth conditions small quantities of the 30-kDa and 45-kDa cytochromes c were present. Based on the apparent molecular masses the 14-kDa, 22-kDa, 30-kDa and 45-kDa cytochromes may also be present in membrane-fractions.
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D002462:Cell Membrane / Q000201:enzymology; D003574:Cytochrome c Group / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D007158:Immunologic Techniques; D008970:Molecular Weight; D010231:Paracoccus denitrificans / Q000201:enzymology* / Q000254:growth & development; D011199:Potentiometry; D012995:Solubility; D013053:Spectrophotometry
chemical_list: D003574:Cytochrome c Group