Table 2.
k
red
(s−1) |
K
d(Al))
(µM) |
k
red
/
K
d
(s−1·mM−1) |
app
k
ox1
(s−1·mM−1) |
|
---|---|---|---|---|
AAO | 115 ± 3 | 31 ± 2 | 3710 ± 258 | 770 ± 40 |
F397Y | 150 ± 3 | 41 ± 3 | 3660 ± 277 | 770 ± 70 |
F397W1 | 124 ± 3 | 292 ± 17 | 425 ± 10 | 689 ± 92 |
F397A | 69 ± 1 | 61 ± 2 | 1130 ± 40 | 78 ± 4 |
F397L | 87 ± 1 | 180 ± 7 | 483 ± 20 | 340 ± 10 |
The constants were measured using stopped-flow rapid spectrophotometry in 50 mM sodium phosphate (pH 6.0) at 12 °C under anaerobic conditions. 1The F397W constants for the first phase of the oxidative half-reaction show a hyperbolic dependence on O2 concentration (in contrast to the other variants) with kox/Kd(ox) and kox values of 689 ± 92 mM−1s−1 and 156 ± 12 s−1 respectively, estimated from fit to equation (5). Means and standard deviations estimated from the fits to equations (3), (4) and (5). All kinetics were measured by triplicates.