Table 2. Comparison of ribonucleotide discrimination in wildtype and mutant Pol μ proteins.
| Enzyme | xNTP | K m (μM) | k cat (s−1) | k cat/Km (s−1·μM−1) | Discrimination |
|---|---|---|---|---|---|
| Pol μ wt | dTTP (4) | 4.0 ± 0.9 | 0.02 ± 0.005 | 5.6 × 10−3 ± 2.2 × 10−3 | |
| UTP (6) | 21 ± 3.0 | 0.04 ± 0.012 | 2.1 × 10−3 ± 0.65 × 10−3 | 2.7 | |
| Pol μ H329A | dTTP (5) | 7.5 ± 1.98 | 0.017 ± 0.005 | 2.2 × 10−3 ± 4.23 × 10−4 | |
| UTP (5) | 65.8 ± 10.8 | 0.005 ± 0.003 | 8.1 × 10−5 ± 3.34 × 10−5 | 27.0 | |
| Pol μ G433A | dTTP (3) | 3.1 ± 0.28 | 0.018 ± 0.006 | 5.8 × 10−3 ± 2.3 × 10−3 | |
| UTP (3) | 29 ± 2.8 | 0.022 ± 0.008 | 0.76 × 10−3 ± 0.23 × 10−3 | 7.6 | |
| Pol μ G433S | dTTP (5) | 6.0 ± 1.4 | 0.026 ± 0.005 | 4.5 × 10−3 ± 1.6 × 10−3 | |
| UTP (5) | 72.7 ± 22.9 | 0.027 ± 0.014 | 0.41 × 10−3 ± 0.28 × 10−3 | 11.0 | |
| Pol μ W434A | dTTP (6) | 9.4 ± 1.13 | 0.032 ± 0.013 | 3.7 × 10−3 ± 1.68 × 10−3 | |
| UTP (3) | 79.1 ± 8.20 | 0.012 ± 0.003 | 1.6 × 10−4 ± 0.56 × 10−4 | 23.0 | |
| Pol μ W434H | dTTP (4) | 6.7 ± 1.62 | 0.020 ± 0.006 | 3.1 × 10−3 ± 1.37 × 10−3 | |
| UTP (3) | 61.1 ± 8.20 | 0.021 ± 0.006 | 3.5 × 10−4 ± 0.88 × 10−4 | 8.8 |
Values represent the mean ± standard deviation for each calculation, with values in parenthesis indicating the number of independent measurements per sample.