TABLE 1.
Kinetic constants of pure, GST-free, recombinant GCK expressed in E. coli
GKA is RO0274375. Means ± S.E. of results of the analysis from three to four protein expression preparations are presented.
| Parameter | GCKWT | GCKK140E | GCKP417R |
|---|---|---|---|
| kcat (s−1) | 62.8 ± 4.11 | 40.0 ± 1.36a | 48.3 ± 7.40 |
| kcat fold increase with GKA | 1.64 ± 0.04 | 1.73 ± 0.07 | 1.46 ± 0.02 |
| Glucose S0.5 (mm) | 7.45 ± 0.26 | 10.8 ± 1.13 | 6.59 ± 0.32 |
| Glucose S0.5 fold decrease with GKA | 3.61 ± 0.45 | 4.52 ± 0.48 | 4.66 ± 0.25 |
| nH | 1.77 ± 1.10 | 1.57 ± 0.13 | 1.52 ± 0.04 |
| nH/nHGKA | 1.11 ± 0.06 | 0.99 ± 0.10 | 1.01 ± 0.02 |
| Km(ATP) (mm) | 0.46 ± 0.02 | 0.35 ± 0.08 | 2.08 ± 0.15a |
| Km(ATP)/Km(ATP)GKA | 1.02 ± 0.19 | 1.14 ± 0.17 | 1.12 ± 0.03 |
| Relative activity index | 1.37 ± 0.16 | 0.78 ± 0.08a | 1.60 ± 0.14 |
| Relative activity index fold increase with GKA | 23.0 ± 2.14 | 22.7 ± 1.69 | 15.0 ± 0.56a |
a p < 0.025 by unpaired t test in comparison with GCKWT.