Table 2.
Kinetic parameters of the natural substrates of the studied enzymes
| Substrate | KM, μM | Ki, μM | Vmax, μM/min·mg | kcat, 1/s | kcat/KM, 1/M·s |
|---|---|---|---|---|---|
| Ribokinase from Thermus sp. 2.9 | |||||
| ATP | 75 ± 11 | – | 13 ± 1 | 6.8 ± 0.7 | 9.1 × 104 |
| D-ribose | 20 ± 6 | 1,700 ± 400 | 13 ± 2 | 7.1 ± 1.2 | 3.5 × 105 |
| PRPP-synthetase 1 from T. thermophilus HB27 | |||||
| ATP | 10 ± 2 | – | 0.71 ± 0.05 | 0.41 ± 0.03 | 4.3 × 104 |
| D-ribose-5 phosphate | 32 ± 6 | – | 0.85 ± 0.11 | 0.49 ± 0.06 | 1.5 × 104 |
| PRPP-synthetase 2 from T. thermophilus HB27 | |||||
| ATP | 12 ± 2 | – | 20 ± 2 | 11 ± 1 | 9.9 × 105 |
| D-ribose-5 phosphate | 40 ± 4 | – | 24 ± 2 | 14 ± 1 | 3.4 × 105 |
| APR-transferase from T. thermophilus HB27 | |||||
| Adenine | 13 ± 2 | – | 6.0 ± 0.4 | 1.9 ± 0.1 | 1.4 × 105 |
| PRPP | 179 ± 35 | – | 9.2 ± 1.1 | 2.9 ± 0.4 | 1.6 × 104 |