Table 2.
Kinetic parameters of wild-type and mutant yeast TyrRS†
| tRNA substrate Enzyme | kcat/Km, s−1 M−1 × 106 | Relative kcat/Km |
|---|---|---|
| Yeast tRNATyr | ||
| TyrRS (wt) | 8.5 | 1 |
| TyrRS-myc | 11.8 | 1.2 |
| TyrRS*5 | 3.1 | 0.36 |
| TyrRS*9 | 6.7 | 0.79 |
| TyrRS*10 | 3.6 | 0.54 |
| Suppressor tRNA | ||
| TyrRS (wt) | 0.014 | 1 |
| TyrRS-myc | 0.0067 | 0.48 |
| TyrRS*5 | 0.0077 | 0.55 |
| TyrRS*9 | 0.015 | 1.1 |
| TyrRS*10 | 0.0059 | 0.42 |
| E. coli tRNAPro | ||
| TyrRS (wt) | 0.0061 | 1 |
| TyrRS-myc | 0.0016 | 0.26 |
| TyrRS*5 | 0.0015 | 0.24 |
| TyrRS*9 | 0.0010 | 0.16 |
| TyrRS*10 | 0.00061 | 0.10 |
†
Kinetic parameters listed are the average of two or more experiments. The tRNA concentrations varied from 0.067 to 5× Km. Enzyme concentrations ranged from 0.05 nM to 730 nM, depending on the tRNA used.