Table I.
Kinetic parameters for aurovertin inhibition of ATP hydrolysis.
| System | Model | n(E) | n(ES) | Vmax1 (μmol min−1 mg−1) | Vmax2 (μmol min−1 mg−1) | Km (mM) | Ki(E) (nM) | Ki(ES) (nM) | R2 |
|---|---|---|---|---|---|---|---|---|---|
| Bovine | eq 5 | 1 | 1 | 0.57 ± 0.01 | 0.23 ± 0.01 | 0.36 ± 0.02 | 820 ± 250 | 119 ± 17 | 0.989 |
| Bovine | eq 5 | 2 | 1 | 0.58 ± 0.01 | 0.22 ± 0.01 | 0.33 ± 0.01 | 960 ± 250 | 120 ± 17 | 0.988 |
| E. coli | eq 5 | 2 | 1 | 0.32 ± 0.01 | 0.06 ±0.01 | 0.19 ± 0.01 | 430 ± 70 | 150 ± 20 | 0.981 |
| E. coli | eq 6 | 2 | 1 | 0.31 ± 0.01 | — | 0.18 ± 0.01 | 1100 ± 400 | 290 ± 20 | 0.972 |
Parameters (±SE) were obtained from 3D fits of v, [S], and [I], using either eq 5 or eq 6, as described in Materials and Methods. Vmax1 and Vmax2 are the maximal catalytic rates of the ES and ESI complexes, respectively. Ki(E) and Ki(ES) are the inhibition constants for the competitive and uncompetitive portions of mixed inhibition, respectively. n(E) and n(ES) are the cooperativity factors for the competitive and uncompetitive inhibition constants, respectively. The 3D fits did not converge with the bovine data using either eq 6, or eq 5 when both n(E) and n(ES) are equal to 2.