Properties of bovine heart mitochondrial cytochrome b560.

摘要: A large-scale preparation of the two-subunit protein complex (QPs) that converts succinate dehydrogenase into succinate-ubiquinone reductase from cytochrome b-c1 particles is achieved by a procedure involving Triton X-100 solubilization and calcium phosphate column chromatography at different pH values. The isolated QPs contains 25 nmol b560/mg able to reconstitute with soluble form TTFA-sensitive reductase. maximum reconstitutive activity 100 mumol oxidized per min mg 23 degrees C. Although b560 in not reducible its dithionite reduced reactive carbon monoxide, shown be physically associated following observations. has symmetrical alpha-absorption peak, which upon reconstitution becomes slightly broadened shows shoulder around 553 nm, identical Upon addition QPs, about 50% insensitive monoxide treatment. redox potential -144 mV higher than (-185 mV). dehydrogenase, 46% Cytochrome two epr signals, g = 3.07 2.92, whereas exhibits only one signal 3.46. When reconstituted reductase, 3.46 reappears expense signal. Based on measurement liquid helium temperature, 18% total b active succinate-cytochrome c b560, indicating indeed unique denatured product b562 or b565.