Table 5

Kinetic parameters for activation of meloxicam metabolism by human CYP 3A4 by quinidine and hydroquinidine

V max(pmol/min/mg protein)1311
K s(μM)310270
K a (μM)5032
B 0.99680.9999

Experimental data obtained in the presence of activator (A) were fitted to the velocity equation for mixed-type nonessential activation. Vmax, maximal velocity of the unactivated reaction; Ks, dissociation constant of the enzyme-substrate complex; Ka, dissociation constant of the enzyme-activator complex; β, factor by whichVmax changes when A occupies the enzyme; α, factor by which Ks changes when Aoccupies the enzyme.