Table II.
Rates of Quinonoid Intermediate Formation and Decay Under Single-Turnover Conditions
| Parameter | Succinyl (s−1) | Octanoyl (s−1) | Butyryl (s−1) | β-Hydroxybutyryl (s−1) | Glutaryl (s−1) |
|---|---|---|---|---|---|
| Wild-type ALAS | |||||
| Qf | 6.0 ± 0.6 | 2.3 ± 0.4 | 0.41 ± 0.04 | n/d | 0.220 ± 0.03 |
| Qd1 | 2.00 ± 0.30 | 0.071 ± 0.004 | 0.070 ± 0.005 | n/d | 0.091 ± 0.005 |
| Qd2 | 0.072 ± 0.005 | 0.020 ± 0.003 | 0.011 ± 0.003 | n/d | 0.0010 ± 0.0004 |
| R85K | |||||
| Qf | 4.20 ± 0.1 | 1.91 ± 0.20 | 0.323 ± 0.020 | 0.121 ± 0.021 | 0.192 ± 0.042 |
| Qd1 | 1.10 ± 0.1 | 0.11 ± 0.02 | 0.002 ± 0.0001 | 0.022 ± 0.005 | 0.134 ± 0.071 |
| Qd2 | 0.050 ± 0.004 | 0.070 ± 0.003 | 0.041 ± 0.007 | 0.013 ± 0.001 | 0.0010 ± 0.0001 |
n/d, not determined; Qf, quinonoid intermediate formation; Qd1, first step of quinonoid intermediate decay; Qd2, second step of quinonoid intermediate decay.