Table 2

Kinetic analysis for quinone-type metabolite 3 formation from troglitazone by recombinant P-450 enzymes

P-450 EnzymesKmVmaxVmax/Km
μM min−1 ml/min/nmol
CYP2C82.7  ± 2.54.2  ± 1.01.6
CYP2C93.6  ± 2.90.6  ± 0.10.2
CYP2C193.1  ± 1.82.8  ± 0.30.9
CYP3A4120  ± 547  ± 10.4

Kinetic analysis for metabolite 3 formation of troglitazone were determined with P-450 concentration of 0.025 μM (Supersomes; Gentest) and substrate concentration between 1 and 100 μM. The kinetic parameters were calculated from the fitted curves with the computer program KaleidaGraph.