Table 3.
Effect of Ala mutations on the kinetic parameters of the Hill equation for Glc-1P and Mg2+ saturation curves, as determined with and without 1.5 mM FBP.a
| Glc1P | Mg2+ | ||||
|---|---|---|---|---|---|
| FBP (mM) | S0.5 (mM) | n | S0.5 (mM) | n | |
| WT | 1.5 | 0.023 ± 0.002 | 1.4 ± 0.2 | 1.3 ± 0.1 | 1.8 ± 0.1 |
| 0 | 0.37 ± 0.04 | 1.5 ± 0.1 | 6.0 ± 0.4 | 1.1 ± 0.4 | |
| P103A | 1.5 | 0.17 ± 0.01 | 1.4 ± 0.1 | 1.5 ± 0.2 | 1.0 ± 0.2 |
| 0 | 0.22 ± 0.02 | 1.1 ± 0.1 | 1.5 ± 0.2 | 1.3 ± 0.2 | |
| Q105A | 1.5 | 0.018 ± 0.002 | 1.1 ± 0.2 | 2.0 ± 0.1 | 2.8 ± 0.5 |
| 0 | 0.33 ± 0.01 | 1.8 ± 0.1 | 7.4 ± 1.9 | 1.1 ± 0.1 | |
| Q106A | 1.5 | 0.120 ± 0.009 | 1.3 ± 0.1 | 4.8 ± 1.3 | 1.1 ± 0.2 |
| 0 | 0.25 ± 0.03 | 1.6 ± 0.2 | 4.6 ± 0.4 | 1.9 ± 0.4 | |
| R107A | 1.5 | 0.12 ± 0.02 | 1.0 ± 0.1 | 6.7 ± 1.9 | 1.0 ± 0.2 |
| 0 | 0.26 ± 0.12 | 0.9 ± 0.1 | 6.4 ± 1.2 | 1.3 ± 0.3 | |
| M108A | 1.5 | 0.019 ± 0.002 | 1.1 ± 0.1 | 3.2 ± 0.2 | 2.2 ± 0.3 |
| 0 | 0.24 ± 0.01 | 1.8 ± 0.1 | 4.6 ± 1.6 | 1.3 ± 0.3 | |
| K109A | 1.5 | 0.025 ± 0.001 | 1.6 ± 0.1 | 0.8 ± 0.1 | 1.3 ± 0.2 |
| 0 | 0.27 ± 0.02 | 2.5 ± 0.5 | 4.0 ± 0.3 | 2.8 ± 0.8 | |
| E111A | 1.5 | 0.029 ± 0.002 | 1.9 ± 0.2 | 1.0 ± 0.1 | 1.7 ± 0.3 |
| 0 | 0.39 ± 0.05 | 1.5 ± 2.6 | 4.7 ± 0.9 | 1.4 ± 0.2 | |
| N112A | 1.5 | 0.040 ± 0.009 | 1.5 ± 0.8 | 0.99 ± 0.04 | 4.1 ± 0.7 |
| 0 | 0.363 ± 0.005 | 1.5 ± 0.1 | 4.5 ± 0.5 | 1.7 ± 0.3 | |
| W113A | 1.5 | 0.34 ± 0.07 | 1.3 ± 0.2 | 5.8 ± 1.4 | 1.6 ± 0.4 |
| 0 | 0.46 ± 0.02 | 1.7 ± 0.1 | 5.0 ± 2.0 | 1.6 ± 0.7 | |
| Y114A | 1.5 | 0.27 ± 0.16 | 0.2 ± 0.2 | 6.2 ± 2.1 | 1.2 ± 0.2 |
| 0 | 0.43 ± 0.14 | 0.3 ± 0.2 | 6.9 ± 2.1 | 1.2 ± 0.2 | |
| R115A | 1.5 | 0.143 ± 0.002 | 1.7 ± 0.1 | 5.4 ± 0.6 | 1.3 ± 0.1 |
| 0 | 0.28 ± 0.01 | 1.7 ± 0.1 | 5.4 ± 0.7 | 1.7 ± 0.4 | |
a
Enzyme assays were performed as described in Materials and Methods.