Table 1

Estimated kinetic parameters for the formation of DHPBI from pimozide (0.5–200 μM) and inhibition by ketoconazole or furafylline in HLMs

Incubation withKinetics of DHPBI formation
Km1Vm1Vmax1/Km1Km2Vmax2Vmax2/Km2
Pimozide alone0.37  ± 1.314  ± 1237.534  ± 6.7244  ± 117.2
Pimozide + ketoconazole (1 μM)36  ± 5.434.7  ± 1.6
Pimozide + furafylline (10 μM)0.19  ± 1.217.2  ± 1289.058  ± 21173  ± 143.0

Km1 and Vmax1 refer to Michaelis-Menten parameters for the high-affinity component, whereasKm2 and Vmax2 refer to the low-affinity component.

  • Km is expressed as μM andVmax as pmol/min/mg protein. Values are mean and standard error (S.E.) of estimates of nonlinear least-square regression analysis obtained by WINNONLIN (see, “Materials and Methods”).