Table 4.
Effect of amino acid changes in human GALK on their enzymatic properties and the IC50 of inhibitors 1, 4 and 24
| Mutations | kcat (s−1) | KM of ATP (μM) | KM of Galactose (μM) | Effects on IC50 of compound 1 | Effects on IC50 of compound 4 | Effects on IC50 of compound 24 |
|---|---|---|---|---|---|---|
| T77L | 4.1 | 218.4 | 1305.2 | None | None | None |
| S79N | 4.8 | 303.4 | 1227.3 | None | None | None |
| L145Y | 11.6 | 259.7 | 222.7 | None | None | None |
| LI 45 A | 6.4 | 379.9 | 356.8 | None | None | None |
| W106A | No protein expression | - | - | - | - | - |
| W106T | No protein expression | - | - | - | - | - |
| Y109L | 43.2 | 70.2 | 963.2 | None | None | None |
| Y109A | 8.7 | 579.3 | 268.7 | None | None | None |
| GALK Loop to MVK Loop | 0.1 | 695.4 | 1857.3 | None | None | None |
| SMOG | 2.1 | 8.2 | 141.9 | None | Increased 10-fold | Increased 20-fold |
| L135P | 13.3 | 51.1 | 544.9 | None | None | None |
| R37K | 0.4 | 6.4 | 623.8 | None | None | None |
| R37A | No activity | - | - | - | - | - |
| WT | 17.5 | 20.9 | 319 | - | - | - |