The existence of an antimycin A insensitive ubiquinol-cytochrome c reductase activity in the photosynthetic apparatus.
A nonproteinaceous, antimycin A insensitive ubiquinol-cytochrome c reductase activity is detected in and purified from chromatophores of Rhodopseudomonas sphaeroides, R-26. This activity is about 5 times the antimycin A sensitive reductase activity in chromatophores and the two are not interconvertable. The purification involved chloroform:methanol (2:1), and hexane extractions and florisil column chromatography. The purified preparation contains some bacteriochlorophyll-like pigments and phospholipids, and is stable in organic solvent. It catalyzes the oxidation of ubiquinol by cytochrome c with substrate specificity and pH optimum.
D000968:Antimycin A / Q000494:pharmacology*; D020130:Bacterial Chromatophores / Q000201:enzymology*; D004351:Drug Resistance; D014450:Electron Transport Complex III; D006863:Hydrogen-Ion Concentration; D009097:Multienzyme Complexes / Q000302:isolation & purification*; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification*; D010788:Photosynthesis; D011808:Quinone Reductases / Q000302:isolation & purification*; D012242:Rhodobacter sphaeroides / Q000201:enzymology; D013379:Substrate Specificity
D009097:Multienzyme Complexes; D000968:Antimycin A; D009247:NADH, NADPH Oxidoreductases; D011808:Quinone Reductases; D014450:Electron Transport Complex III