β Scribed by Beverly K. Pierson
No coin nor oath required. For personal study only.
The major types of cytochromes present in Chloroflexus aurantiacus strain J-10-fl were determined by analysis of cell-free preparations and membranes from cells grown phototrophically and chemotrophically. Reduced minus oxidized difference spectroscopy as well as quantitative analysis of the pytidine ferrohemochromogens in alkaline solution were used to determine the classes of cytochromes present.
Evidence for membrane-bound cytochromes of the b and c-type was found in cell-free preparations of phototrophically grown cells. Difference spectra revealed absorption maxima at 553 nm, 523 nm, and 418 nm and a shoulder at 562 nm. Protoheme and heine c were identified as alkaline pyridine ferrohemochromogens with absorption maxima at 556 and 550 nm respectively. The ratio of heme e to protoheme in the cell-free preparation was about 10 to 1 with 0.65 gmol of heine c and 0.067 gmol of protoheme per gram of total cell protein. Dithionite plus carbon monoxide minus dithionite reduced difference spectra of membranes revealed a peak at 414 nm and troughs at 552, 523, and 423 nm consistent with a CO-binding cytochrome c.
Similar analyses of chemotrophically grown cells revealed evidence for the presence of membrane-bound cytochromes of the c, b, and a classes with absorption maxima at 5 5 2 -557 and 593 -596 nm. Protoheme, heme c and heme a were detected as pyridine ferrohemochromogens with maxima at 556, 550, and 588 nm respectively. The ratio of heine c to protoheme was about 3 to 1 with 0.44 gmol of heine c and 0.16 gmol of protoheme per gram of total cell protein.
π SIMILAR VOLUMES