TABLE 1.
Kinetic parameters of wild-type ChPPK and variant ChPPK/A79G/S106C/I108F/L285P
| Variable substrates | Constant substrates | Measured products | PPKs | Km or Kprime (mM or g/L) |
k
cat
(s−1) |
Ki (mM or g/L) |
k cat/Km or k cat/Kprime (S−1 M−1) |
|---|---|---|---|---|---|---|---|
| AMP | PPA | ADP | Wild-type ChPPK a | 1.63 ± 0.35 d , f | 9.19 ± 1.07 | 10.3 ± 2.6 d | 5.64 |
| Variant ChPPK/A79G/S106C/I108F/L285P a | 1.45 ± 0.26 d , f | 16.3 ± 1.5 | 13.3 ± 3.0 d | 11.2 | |||
| ADP | PPA | ATP | Wild-type ChPPK b | 0.509 ± 0.071 d , g | 4.40 ± 0.09 | NA h | 8.64 |
| Variant ChPPK/A79G/S106C/I108F/L285P b | 0.259 ± 0.050 d , g | 3.10 ± 0.05 | NA h | 12.0 | |||
| AMP | PPA | ATP | Wild-type ChPPK a | 2.26 ± 0.63 d , f | 4.78 ± 0.94 | 2.40 ± 0.67 d | 2.12 |
| Variant ChPPK/A79G/S106C/I108F/L285P a | 1.02 ± 0.13 d , f | 41.7 ± 2.6 | 9.36 ± 1.36 d | 40.9 | |||
| PPA | AMP | ATP | Wild-type ChPPK a | 1.96 ± 0.85 e , f | 4.35 ± 1.27 | 2.34 ± 0.98 e | NA h |
| Variant ChPPK/A79G/S106C/I108F/L285P a | 0.800 ± 0.121 e , f | 38.6 ± 2.2 | 22.1 ± 4.7 e | NA h | |||
| ATP | PPA | ADP | Wild-type ChPPK c | 3.65 ± 0.67 d , f | 0.720 ± 0.529 | NA h | 0.197 |
| Variant ChPPK/A79G/S106C/I108F/L285P c | 1.36 ± 0.19 d , f | 0.460 ± 0.016 | NA h | 0.388 | |||
| ATP | PPA | AMP | Wild-type ChPPK c | 4.40 ± 0.62 d , f | 0.130 ± 0.008 | NA h | 0.0295 |
| Variant ChPPK/A79G/S106C/I108F/L285P c | 0.440 ± 0.084 d , f | 0.0557 ± 0.0112 | NA h | 0.136 | |||
| ADP | PPA | AMP | Wild-type ChPPK b | 1.75 ± 0.23 d , g | 1.09 ± 0.03 | NA h | 0.623 |
| Variant ChPPK/A79G/S106C/I108F/L285P b | 2.75 ± 0.34 d , g | 2.07 ± 0.04 | NA h | 0.753 |
The data were fitted to the substrate inhibition equation. The equation is given by: V = Vmax × [S] / (Km + [S] × (1 + [S] / Ki)), where V is the reaction rate, Vmax indicates the maximum enzyme activity, [S] is the substrate concentration, Km indicates the Michaelis constant, and Ki indicates the dissociation constant.
The data were fitted to the allosteric sigmoidal equation. The equation is given by: V = Vmax × [S]^h / (Kprime + [S]^h), where V is the reaction rate, Vmax indicates the maximum enzyme activity, [S] is the substrate concentration, h indicates the Hill slope, and Kprime is related to the Michaelis constant.
The data were fitted to the Michaelis–Menten equation. The equation is given by: V = Vmax × [S] / (Km + [S]), where V is the reaction rate, Vmax indicates the maximum reaction rate when the enzyme is fully saturated with substrate, [S] is the substrate concentration, and Km indicates the Michaelis constant.
mM.
g/L.
Km.
Kprime.
Not available.