Table 1.
Apparent kinetic constants of CDH IIA and CDH IIB for electron donors determined with lactose (30 mM) in McIlvaine buffer at the indicated pH valuesa
| Electron acceptor | Stoichiometry | pH | CDH IIA |
CDH IIB |
||||
|---|---|---|---|---|---|---|---|---|
| Mean Km (μM) ± SD | Mean kcat (s−1) ± SD | kcat/Km (mM−1 s−1) | Mean Km (μM) ± SD | Mean kcat (s−1) ± SD | kcat/Km (mM−1 s−1) | |||
| Cytochrome c | 2 | 6 | 67.9 ± 5.8 | 64.8 ± 1.7 | 954 | 6.7 ± 1.0 | 9.4 ± 0.3 | 1,403 |
| FcPF6 | 2 | 6 | 5.2 ± 0.2 | 75.4 ± 2.1 | 14,500 | 31.5 ± 7.5 | 19 ± 0.7 | 603 |
| 1,4-Benzoquinone | 1 | 6 | 26.2 ± 3.0 | 49.2 ± 0.7 | 1,878 | 24.3 ± 0.1 | 9.9 ± 0.4 | 407 |
| DCIP | 1 | 5 | 33.6 ± 4.8 | 38.1 ± 0.8 | 1,134 | 25.3 ± 5.8 | 7.4 ± 0.6 | 292 |
a
The sample standard deviation was calculated from data from 3 experiments.