Table 3.
Initial-Rate Parameters — WT and Direct-Contact Mutants
| Enzyme1 | Ki Quc (μM)2 | (−) Quercetin | ||
|---|---|---|---|---|
| kcat (s−1)3 | Km paps (μM)4 | Km 1-HP (μM)3 | ||
| WT | 0.32 (0.2)5 | 3.4 (0.2) | 350 (20) | 3.8 (0.3) |
| W13A | 7.5 (0.5) | 3.2 (0.3) | 360 (30) | 4.2 (0.3) |
| W98A | 5.3 (0.4) | 3.5 (0.2) | 310 (20) | 3.6 (0.2) |
| Y257A | 1.6 (0.2) | 3.6 (0.4) | 370 (30) | 4.0 (0.3) |
1
Enymes all harbor the phosphomimetic S347D mutation.
2
Determined at saturating PAPS (300 μM, 910 × Km) and 1-HP (100 μM, 26 × Km).
3
Determined at saturating PAPS (300 μM, 910 × Km).
4
Determined at saturating 1-HP (100 μM, 26 × Km).
5
Values in parentheses indicate one standard deviation unit.
2–4
Initial-rate protocols are described in Materials and Methods.