Table 4. Kinetic parameters of wild-type and mutant GST-CK1δ fusion proteins.
| CK1δ mutant | Vmax | Km [µM] |
| wild-type | 8.506 (±0.493) | 4.843 (±0.590) |
| S328A | 12.660 (±0.767) | 5.487 (±0.668) |
| S370A | 21.320 (±1.676) | 7.378 (±1.025) |
| T397A | 12.660 (±1.467) | 7.200 (±1.528) |
| S328A, S370A | 20.810 (±1.461) | 5.312 (±0.723) |
| S328A, T397A | 22.300 (±1.699) | 6.630 (±0.925) |
| S328A, S370A, T397A | 20.310 (±1.802) | 7.739 (±1.227) |
Identified Chk1 target residues in GST-wt CK1δ (FP449) were exchanged to alanine and the kinetic parameters of the resulting mutants were determined using α-casein as substrate. Data were fitted to the Michaelis-Menten equation. Obtained Vmax and Km values are reported in table 4. Vmax is expressed as pmol phosphate transferred per minute per mg of recombinant kinase. Standard error values are indicated in parentheses.