Table 1.
Kinetic parameters of the Pyrococcus furiosus TrpSa
| Substrate | kcat substitution (s−1) | kcat deamination (s−1) | KM amino acid (mM) | KM indole (μM) | kcat/ KM amino acid (M−1s−1) | kcat/ KM indole (M−1s−1) | Coupling Efficiencyb (indole) | Coupling Efficiencyb (IGP) |
|---|---|---|---|---|---|---|---|---|
| L-Ser | 1.0 ± 0.1c | 0.055 ± 0.002 | 0.6 ± 0.1c | 20 ± 2c | 1,600 | 50,000 | >99% | >99% |
| L-Thr | 0.61 ± 0.04 | 0.47 ± 0.04 | 1.3 ± 0.2 | 1,400 ± 300d | 470 | 460 | 65 ± 10% | 17 ± 3% |
a
Errors were estimated from three independent experiments. All reactions conducted with 1–20 μM PfTrpS in potassium phosphate buffer pH 8.0.
b
Defined as the proportion of 1 equivalent of indole or IGP that reacts with a single equivalent of Ser or Thr to form product.
c
These values from Ref. 5.
d
This value was obtained by merging initial velocity data (shown in Figure S3) collected from the UV-vis and LC-MS.