TABLE 3

Cytochrome P450 substrates used for the activity cocktail assay

Cytochrome P450SubstrateConc.MetaboliteActivity of HLM PoolaKMb
μMpmol/(mg · min)μM
CYP1A2Phenacetin50Acetaminophen829 ± 12.541
CYP2B6Bupropion5Hydroxybupropion4 ± 0.14110
CYP2C8Amodiaquine5N-Desethylamodiaquine847 ± 1.32.1
CYP2C9Tolbutamide1004-Hydroxytolbutamide70 ± 1.3147
CYP2C19S-Mephenytoin1004-Hydroxymephenytoin82 ± 0.957
CYP2D6Propafenone55-Hydroxypropafenone225 ± 5.60.5
CYP3A4Atorvastatin35o-Hydroxyatorvastatin288 ± 15.650
  • HLM, human liver microsome.

  • a Activities were determined in an HLM pool by a single incubation of each substrate at the indicated concentration. Values represent the mean ± S.D. of triplicate experiments.

  • b Apparent KM values were determined in an HLM pool by incubation of each substrate alone in an appropriate concentration range. The values for tolbutamide 4-hydroxylation and S-mephenytoin 4-hydroxylation were taken from the literature (Walsky and Obach, 2004).