TABLE 3

Kinetic analysis of etoposide catechol formation by recombinant human P450s

The kinetic constants were determined according to Lineweaver-Burk double-reciprocal plots. The values (Km and Vmax) are reported as mean ± S.D. (n = 3).

P450s
Km
Vmax
Vmax/Km
μM pmol/min/nmol P450 μl/nmol P450/min
CYP3A4 77.7 ± 27.8a 314 ± 84b 4.0
CYP3A5 13.9 ± 3.1c 19.4 ± 0.4d 1.4
CYP2E1
26.0 ± 10.5
3.4 ± 1.2
0.1

  • ↵ a Statistically different from Km of CYP3A5 and CYP2E1 (p < 0.033).

  • ↵ b Statistically different from Vmax of CYP3A5 and CYP2E1 (p < 0.04).

  • ↵ c No different from Km of CYP2E1 (P = 0.128).

  • ↵ d Statistically different from Vmax of CYP2E1 (p < 0.017).