Figure 6

Oxidation of membrane-bound cytochrome c by 2-hydroxyphenazine. The 100-μl reaction mixture consisted of membranes (750 μg protein), 4 μM ferredoxin 1 mM NADPH and1 μg FNR contained in 50 mM MOPS buffer (pH 6.8). The reduction of cytochrome c was initiated by addition of FNR. The reduction and re-oxidation was monitored at 554 nm. When fully reduced, 200 μM 2-hydroxyphenazine (2 μl) was added (arrow). Panel A, time course for the reduction and re-oxidation by 2-hydroxyphenazine added at the arrow. Panel B, reduced minus oxidized UV-visible spectra of membranes before (lower trace) and after (upper trace) addition of 2-hydroxyphenazine.