TABLE 3

Kinetic parameters for the formation of 8-hydroxyefavirenz from efavirenz in recombinant human P450s

Kinetic data are presented as amean ± S.D. (n = 3 independent experiments performed in duplicate) or bparameter estimated, with standard error of parameter estimates obtained from WinNonlin in parentheses. Kinetic parameters were estimated by fitting the velocity vs. substrate concentrations to single site Michaelis-Menten equation.


Kinetic Parameters

CYP2B6a

CYP2B6 + b5b

CYP1A2b

CYP3A5b

CYP3A4b
Vmax (pmol/min/pmol P450) 5.20 ± 0.76 3.50 (0.07) 0.60 (0.04) 0.60 (0.03) 0.16 (0.01)
Km (μM) 12.40 ± 1.80 6.40 (0.5) 8.30 (2.40) 19.10 (3.14) 23.50 (3.10)
Vmax/Km (μl/min/pmol P450)
0.42 ± 0.06
0.55
0.07
0.03
0.007