TABLE 4

Kinetic constants of major paclitaxel oxidation in rat, minipig, regular pig, and human liver microsomes Substrate concentrations used for paclitaxel oxidation were 2.5 to 25 μM. Results are presented as means ± S.D. (n = 3).


Microsomes

Paclitaxel Hydroxylation

P450 Enzymes

Km

Vmax

Vmax/Km
μM pmol/min/mg protein
Untreated rata C3′ CYP3A1/2 16 ± 2 20 ± 12 1.2
PCN-treated rata C3′ CYP3A1/2 25 ± 4 184 ± 11 7.5
Minipig Unknown Possible CYP3A29 15 ± 2 29 ± 4 1.9
Pig Unknown Possible CYP3A29 17 ± 3 14 ± 3 0,8
Human sample H6a

CYP 2C8
9 ± 5
61 ± 40
6.5
  • a Kinetic parameters reported in Vaclavikova et al. (2003)