TABLE 1.
Comparison of electron transfer and superoxide-generating activities of various cytochrome bc1 complexes
Rsbc1, wild-type, 4 subunit R. sphaeroides bc1; RsΔIV, Rsbc1 lacking subunit IV; Cyt b(H198N), Rsbc1 lacking heme bL; Cyt b(H111N), Rsbc1 lacking heme bH; XO, xanthine oxidase. Each data point represents an average of four experiments.
| Preparation | Activities |
||
|---|---|---|---|
| Electron transfer (μmol of cytochrome c reduced/min/nmol of cytochrome c) | O2˙̄ generation (milliunits of XO/nmol of cytochrome c) |
||
| −Antimycin | +Antimycin | ||
| Mitochondrial bc1 | 43.0 ± 0.3 | 15 ± 2 | 19 ± 2 |
| Rsbc1 | 3.5 ± 0.2 | 91 ± 2 | 300 ± 2 |
| RsΔIV | 0.8 ± 0.2 | 325 ± 2 | 546 ± 5 |
| Cyt b(H198N) | 0.4 ± 0.2 | 510 ± 5 | 510 ± 5 |
| Cyt b(H111N) | 0.3 ± 0.2 | 500 ± 4 | 510 ± 6 |