Table 2

Enzyme kinetic parameters for formation of D-617 and norverapamil in human liver microsomes from two livers after incubation with verapamil and without addition of an inhibitor (Vmax,Km) and respective Ki values for inhibition of these reactions by piperine

D-617Norverapamil
Liver 1Liver 2Liver 1Liver 2
V max(pmol/min/mg protein)728  ± 1021070  ± 701051  ± 1331482  ± 78
K m(μM)90  ± 2176  ± 1085  ± 1867  ± 8
K i (μM)36  ± 849  ± 644  ± 1077  ± 10