Table 2. Electrochemical and Kinetic Properties of ChCDH Variantsa.
| +375
mM KCl |
no KCl |
|||||||
|---|---|---|---|---|---|---|---|---|
| variant | E° (mV vs SHE) | J′a (μA cm–2) | cyt c, kcat (s–1) | k2 (s–1) | k1 (s–1) | k2 (s–1) | k1 (s–1) | IPET (M–1 s–1) |
| ChCDH | 141 | 2.51 | 0.51 ± 0.01 | 1.47 ± 0.09 | 13.8 ± 1.1 | 0.17 ± 0.01 | 13.6 ± 0.3 | 9.87 × 105 |
| Tyr99Phe | 152 | 1.28 | 0.12 ± 0.01 | 0.43 ± 0.02 | 14.3 ± 0.2 | 0.12 ± 0.01 | 14.4 ± 0.2 | 2.58 × 105 |
| Tyr99Leu | 133 | 0.89 | 0.11 ± 0.01 | 0.25 ± 0.01 | 13.2 ± 0.3 | 0.10 ± 0.01 | 13.6 ± 0.3 | 2.10 × 105 |
a
E°, electrochemical midpoint potentials of the heme b cofactors. J, current densities. cyt c, cytochrome c. k1, FAD reduction. k2, intraprotein electron transfer between the FADH2 and heme b cofactors. IPET, interprotein electron transfer between heme b and NcLPMO9C. Current densities at 250 mV vs SHE after subtraction of the capacitive current (blank).