Table 4

Michaelis-Menten parameters of meloxicam metabolism by recombinant human CYP 3A4 in the presence of quinidine and hydroquinidine, respectively

μM pmol/min/mg protein μl/min/mg protein
Quinidine1 μM400190.99760.05
Quinidine10 μM250400.99500.16
Quinidine50 μM170640.99820.39
Quinidine100 μM180830.99860.47
Hydroquinidine1 μM440230.99830.05
Hydroquinidine5 μM230440.99880.19
Hydroquinidine10 μM160520.99640.33
Hydroquinidine100 μM100930.99810.90

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).