TABLE 3.
Kinetic parameters of IPK1 alanine mutants for IP5
Data represent the mean ± S.D. of triplicate experiments. The last column indicates the IP phosphate that interacts with the mutant side chain, either directly or indirectly, through ordered water molecules. ND, no activity detected.
| Mutant | Km | kcat | PO4 interaction |
|---|---|---|---|
| μm | min−1 | ||
| R45A | 54.28 ± 9.07 | 27.16 ± 1.79 | 3 |
| R130A | ND | ND | 1 |
| K168A | ND | ND | 2 |
| K170A | ND | ND | 5, 6 |
| R192A | 59.35 ± 13.41 | 22.01 ± 2.05 | 5 |
| H196A | 43.48 ± 15.62 | 34.12 ± 4.33 | 5 |
| K200A | 39.79 ± 19.52 | 16.74 ± 2.77 | 6 |
| N238A | 33.72 ± 7.918 | 14.74 ± 1.07 | 6 |
| N239A | 83.30 ± 9.53 | 15.89 ± 0.87 | 6 |
| D368A | ND | ND | 2 |
| K411A | ND | ND | 3, 4 |
| R415A | 62.27 ± 21.89 | 38.71 ± 5.73 | 3, 4 |
| Y419A | 76.86 ± 16.94 | 41.62 ± 4.25 | 4 |