The membrane-boundbandc-type cytochromes ofProteus mirabilisgrown under different conditions
✍ Scribed by John E. Wielink; Willem N. M. Reijnders; L. Fred Oltmann; Frans J. Leeuwerik; Adriaan H. Stouthamer
- Book ID
- 104761300
- Publisher
- Springer
- Year
- 1983
- Tongue
- English
- Weight
- 636 KB
- Volume
- 134
- Category
- Article
- ISSN
- 0302-8933
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✦ Synopsis
The b and c-type cytochromes present in cytoplasmic membranes of Proteus mirabilis, which had been grown under different conditions, were characterized by means of analysis of 77K spectra monitored at different oxidationreduction potentials.
After aerobic growth as well as after anaerobic growth in the presence and absence of nitrate one or more high midpoint potential b-type cytochromes were found (E; approx. 150 mV). Especially after aerobic growth the contribution of this cytochrome (these cytochromes) to the absorbance in the 535-575 nm region of 77K spectra was very large (63 ~). 29 % could be attributed to an a-band at about 563 nm and 34 % to an a-band at 556 nm. After anaerobic growth in the presence of nitrate the high potential cytochrome(s) yielded a-bands at about 561 nm (7%) and 556 nm (31%) and after anaerobic growth in the absence of a terminal electron acceptor a-bands were found at about 560 nm (26 %) and 555 nm (13 %).
b-Type cytochromes with midpo!nt potentials between 10 and 50 mV were found after both aerobic-and anaerobic growth conditions. Especially after anaerobic growth in the presence of nitrate the contribution ofa cytochrome b-556 (E; = 24 mV) to the absorbance band between 535 and 575 nm was very large (57 %). After aerobic growth the contribution of cytochrome b-557 (E; = 49 mV) was 22 %, while after anaerobic growth in the absence of a terminal electron acceptor the contribution of cytochrome b-557 (E; = 10 mV) Was only 14%.
Low potential b-type cytochromes were especially found after anaerobic growth in the absence of a terminal electron acceptor; 21% cytochrome b-556 (E~ = -121 mV) and 19 % cytochrome b-557 (E~ = -242 mV). After aerobic growth 14 % cytochrome b-556 was found with a midpoint potential of about -106 mV.
A small percentage cytochrome c (2,, about 548 -549 nm) was found in the three types of cells. Its midpoint potential was about 75 inV.