%0 Journal Article %A Dokter, Paul %A Van Wielink, John E. %A Geerlof, Arie %A Oltmann, L. Fred %A Stouthamer, Adriaan H. %A Duine, Johannis A. %T Purification and partial characterization of the membrane-bound haem-containing proteins from Acinetobacter calcoaceticus LMD 79.41 %D 1990 %J Microbiology, %V 136 %N 12 %P 2457-2464 %@ 1465-2080 %R https://doi.org/10.1099/00221287-136-12-2457 %I Microbiology Society, %X Cytoplasmic membranes of Acinetobacter calcoaceticus cells, cultured under acetate-limiting conditions, contain cytochrome b554 and a cytochrome o-containing oxidase. Both have been purified to homogeneity and characterized. Cytochrome b554 is a monomeric protein (molecular mass 70 kDa) with a midpoint potential of +100 mV (in the membrane it has most probably a value of +50 mV). The cytochrome o-containing oxidase seems to be an αβγδ protein since the molecular mass of the native protein was estimated to be 150 kDa and the molecular masses of the subunits, determined by SDS-polyacrylamide-gel electrophoresis, are 55, 41, 33 and 17 kDa. Redox spectroscopy of the purified complex shows the presence of a cytochrome b 555/563 having a midpoint potential of approximately +160 mV (both in purified form and in the membrane). CO difference spectroscopy shows the presence of a second b-type cytochrome, viz. cytochrome, o. Cytoplasmic membranes of A. calcoaceticus cells grown under oxygen-limiting conditions also show the presence of the cytochrome b 554 and the cytochrome o-containing oxidase. In addition a protein has been solubilized with the spectral characteristics of a cytochrome d-containing oxidase. The cytochrome o- and d-containing oxidases appear to be similar to those reported for Escherichia coli and Proteus mirabilis. On the other hand, cytochrome b554 has no counterpart in these organisms since the cytochrome b556 described for E. coli is quite dissimilar. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-136-12-2457