Michaelis-Menten parameters of meloxicam metabolism by recombinant human CYP 3A4 in the presence of quinidine and hydroquinidine, respectively
| Activator | Km | Vmax | B | Vmax/Km | |
|---|---|---|---|---|---|
| μM | pmol/min/mg protein | μl/min/mg protein | |||
| Without | 550 | 16 | 0.9945 | 0.03 | |
| Quinidine | 1 μM | 400 | 19 | 0.9976 | 0.05 |
| Quinidine | 10 μM | 250 | 40 | 0.9950 | 0.16 |
| Quinidine | 50 μM | 170 | 64 | 0.9982 | 0.39 |
| Quinidine | 100 μM | 180 | 83 | 0.9986 | 0.47 |
| Hydroquinidine | 1 μM | 440 | 23 | 0.9983 | 0.05 |
| Hydroquinidine | 5 μM | 230 | 44 | 0.9988 | 0.19 |
| Hydroquinidine | 10 μM | 160 | 52 | 0.9964 | 0.33 |
| Hydroquinidine | 100 μM | 100 | 93 | 0.9981 | 0.90 |
Apparent Km and Vmax with and without activator were calculated from V/S plots by nonlinear regression analysis to the equation for one enzyme kinetics (mean of duplicate experiments).