Table 1.
Effect of KCl on the kinetic parameters of Pfk-2
| Control | 50 mM KCl | |
|---|---|---|
| akcat, s−1 | 61 ± 8 | 60 ± 9 |
| aKM ATP, μM | 8 ± 3 | 14 ± 4 |
| aKi, μM | 1026 ± 100 | 129 ± 55 |
| bKM fructose-6-P, μM | 6–10 | 10 |
| cKd fructose-6-P, μM | 6–8 | 8–10 |
a
Values obtained by fitting to an uncompetitive model of substrate inhibition. The initial velocity obtained as a function of MgATP using a fixed concentration of 0.2 mM fructose-6-P.
b
KM values for fructose-6-P extrapolated to zero concentration MgATP.
c
Values of Kd obtained from intrinsic fluorescence measurements (data not shown). Measurements obtained from b-c2 or a3 independent experiments.