Table 4.
Rate constants for the reactions of WT and E332A TH complexes with O2 at 5 °C.
| FeIITH + O2 →FeIIITH(mM−1s−1) | ||||
|---|---|---|---|---|
| FeIITH-[ ] | 0.037 | |||
| FeIITH + O2 ⇔ FeIITH:O2 | FeIITH:O2 → FeIIITH (s−1) | 6MPH4 → q-6MPH2 (mM−1s−1) | ||
| kon (mM−1s−1) | koff (s−1) | |||
| FeIITH-[6MPH4] | 1.5 | 0.5 | 0.16 | 40 |
| apoTH-[6MPH4] | 0.00017 | |||
| FeIITH-[5-deaza-6MPH4] | No reaction | |||
| FeIITH-[6MPH2] | 2.0 | 0.5 | 0.032 | |
| FeIITH-[L-tyr] | 2.0 | 0.5 | 0.040 | |
| FeIITH-[5-deaza-6MPH4, L-tyr] | 2.0 | 0.4 | 0.026 | |
| FeIITH-[6MPH2, L-tyr] | 6.0 | 0.5 | 0.050 | |
|
| ||||
| FeIITH:O2 → FeIV=O + 4a-HO-6MPH3 | ||||
|
| ||||
| FeIITH-[L-tyr, 6MPH4] | 300 | 50 | 24 s−1 | |
|
| ||||
| FeIITH:O2 → FeII+ HOO-6MPH3 | ||||
|
| ||||
| E332A-[L-tyr, 6MPH4] | 10 | 3 | 0.3 s−1 | |