TABLE 1

Enzymatic kinetic parameters for P450 in human liver microsomes


Enzyme

Assay

Type

Km

Vmax
μM pmol/min/mg pro
CYP1A2 Phenacetin-O-deethylation Simple 75 516
CYP2C9 Diclofenac 4-hydroxylation Substrate inhibition 6.8 3657
CYP2D6 Dextromethorphan O-demethylation Simple 5 1300
CYP3A4 Testosterone 6β-hydroxylation Simple 75 6130
CYP3A4
Midazolam 1-hydroxylation
Substrate inhibition
3.5
1200