Table 1.
Kinetic parameters for the fast and intermediate of phases binding of MgTNP-ATP to pyruvate carboxylase.
| Fast Phase | k1 | k-1 | K1 | R2 |
|---|---|---|---|---|
| Fit to eq (v) | 8.7 ± 0.8 μM-1s-1 | 162 ± 19 s-1 | 18 ± 1 μM | 0.967 |
| Fit to eq (vi) | 0.20 ± 0.01 μM-2s-1 | 244 ± 5 s-1 | 1252 ± 65 μM2 | 0.967 |
| Intermediate Phase | k2 | k-2 | K2 | |
| Fit to eq (vii) | 31 ± 1 s-1 | 0.6 ± 0.6 s-1 | 0.02 ± 0.02 | 0.935 |
| Fit to eq (viii) | 22.6 ± 0.7 s-1 | 10.5 ± 0.2 s-1 | 0.47 ± 0.05 | 0.969 |
| Fit to eq (ix) | 0.50 ± 0.02 μM-1s-1 | 10.6 ± 0.2 s-1 | 21 ± 1 μM | 0.977 |
| Fit to eq (x) | 0.58 ± 0.03 μM-1 s-1 | 12.6 ± 0.2 s-1 | 24 ± 12 μM | 0.937 |
| Fit to eq (xi) | 0.013 ± 0.001μM-2s-1 | 12.7 ± 0.2 s-1 | 1015 ± 67 μM2 | 0.928 |
| Fit to eq (xii) | 0.016 ± 0.001 μM-2 s-1 | 13.5 ± 0.3 s-1 | 863 ± 71 μM2 | 0.880 |
Values of parameters given ± standard errors derived from the least squares regression analysis of the data in Fig 8. K1 is the dissociation constant of the of the enzyme.MgTNP-ATP complex formed in the fast phase whilst K2 is either an equilibrium constant that describes the equilibrium between two conformational states of the enzyme.MgTNP-ATP complex formed in the fast phase (eqs vii and viii) or the dissociation constant of the enzyme.MgTNP-ATP complex formed in the intermediate phase, involving the binding of one or two more MgTNP-ATP molecules. Both K1 and K2 were calculated from the ratios k-1/k1 and k-2/k2 respectively.