Membrane-Bound Cytochromes in a Sulfate-Reducing Strict AnaerobeDesulfovibrio vulgarisMiyazaki F

Cytoplasmic membranes were isolated from the cells of a sulfate-reducing strict anaerobeDesulfovibrio vulgarisMiyazaki F and membrane-bound cytochromes were characterized. Redox difference spectra at 77 K revealed the presence of cytochromes with the α peaks at 552 and 556 nm while CO-binding difference spectra showed the presence ofo-type cytochrome(s). Partial purification of the cytochromes demonstrated that the membranes contain cytochromesc550,c551,c556and possiblyd1besides high molecular mass cytochromecand cytochromec3. It turned out that two kinds of novel CO-bindingc-type cytochromes are present in the membrane. The membranes and a partially purified fraction showed weak ubiquinol-1 oxidase activity but no cytochromecoxidase activity. Results suggest thatD. vulgarisdoes not express the heme-copper terminal oxidase under our growth conditions in spite of the presence of thecolgene, which is homologous to the gene of subunit I of theaa3-type oxidase.