Table 2.
Kinetic Constants for VcMTAN and Mutants Determined Using the Luminescence-Based Assay
| MTAN | KM (nM) | kcat (s−1) | kcat/KM (×106 M−1 s−1) | Ki,MTDIA (pM) | Ki,BuTDIA (pM) | Ki (MTDIA/BuTDIA) |
|---|---|---|---|---|---|---|
| VcMTAN | ||||||
| WT | 61 ± 6 | 0.18 ± 0.01 | 3.0 ± 0.3 | 2.7 ± 0.2 | 0.21 ± 0.04 | 13 |
| A113P | 262 ± 29 | 0.17 ± 0.01 | 0.7 ± 0.1 | 62 ± 7 | 2.4 ± 0.5 | 26 |
| V153I | 430 ± 47 | (7.9 ± 4) × 10−3 | (1.8 ± 2) × 10−2 | NAa | NAa | NAa |
| DOUBLE | 202 ± 23 | (7.4 ± 3) × 10−2 | 0.4 ± 0.1 | 3.0 ± 0.5 | 10.3 ± 1.2 | 0.3 |
| TRIPLE | 536 ± 122 | 0.11 ± 0.01 | 0.2 ± 0.1 | 166 ± 22 | 3.3 ± 0.5 | 50 |
| EcMTAN | 139 ± 18 | 0.32 ± 0.01 | 2.3 ± 0.3 | 0.16 ± 0.02 | 0.20 ± 0.04 | 0.8 |
a
Not available.