Table 1. Apparent kinetic parameters of M. mazei PylRS variants for amino acid activation.
| Enzyme | Amino acids | KM (μM × 103) | kcat (s−1 × 10−2) | kcat/KM (μM−1s−1 × 10−5) | Relative catalytic efficiency | UAG translation efficiency |
|---|---|---|---|---|---|---|
| MmPylRS1 | Pyl | 0.05 ± 0.008 | 29.8 ± 1.2 | 596 | 100 | 15± 1.5 |
| BtaRS | 3-I-Phe | 0.95 ± 0.11 | 8.9 ± 0.3 | 9.37 | 1.6 | 44 ± 5.1 |
| 3-CF3-Phe | 1.44 ± 0.20 | 11.2 ± 0.5 | 7.78 | 1.3 | 39 ± 4.9 | |
| 3-Br-ThA | 1.13 ± 0.35 | 7.3 ± 0.8 | 6.46 | 1.1 | 2 ± 1.0 | |
| Bta | 0.37 ± 0.07 | 5.3 ± 0.2 | 14.3 | 2.4 | 38 ± 6.4 | |
| Trp | NDb | ND | - | - | - | |
| MFRS | 3-I-Phe | 3.18 ± 0.53 | 19.3 ± 1.5 | 6.07 | 1.0 | 47 ± 5.7 |
| 3-CF3-Phe | 2.16 ± 0.21 | 9.9 ± 0.4 | 4.58 | 0.77 | 41 ± 6.3 | |
| 3-Br-ThA | 1.55 ± 0.34 | 6.9 ± 0.7 | 4.45 | 0.75 | 8 ± 0.9 | |
| IFRSa | 3-I-Phe | 0.82 ± 0.09 | 8.71 ± 0.33 | 10.6 | 1.8 | 48 ± 0.1 |
| 3-CF3-Phe | 1.13 ± 0.10 | 7.29 ± 0.21 | 6.45 | 1.1 | 53 ± 2.3 | |
| 3-Br-ThA | 1.57 ± 0.32 | 4.43 ± 0.27 | 2.82 | 0.47 | 7 ± 0.9 |
aKinetic data were adapted from previous work (20).
bND represents not detectable.