Table 1

P450 activities in human liver microsomes

Substrate ConcentrationActivity1-aCorrelation Coefficient (r)
RangeMeanPL-PHOS (0.1 mM CHCl3)PL-PHOS (5 mM CHCl3)PL-RAD (5 mM CHCl3)
mM
PL-PHOS formation1-b 0.10.46–3.631.19
PL-PHOS formation1-b 50.41–23.935.25
PL-RAD formation1-b 53.00–28.8315.29
Caffeine N3-demethylation5–6027.730.6581-150 0.0460.5831-150
(1A2)
Coumarin 7-hydroxylation57–4,1111183.180.0470.7771-160 0.158
(2A6)
S-Mephenytoin-N-demethylation50–306132.090.2680.3280.192
(2B6)
Tolbutamide methyl hydroxylation70–736310.270.6861-150 0.4200.5831-150
(2C9)
S-mephenytoin 4′-hydroxylation4–464110.000.2240.4220.118
(2C19)
DextromethorphanO-demethylation29–550227.750.1980.0200.200
(2D6)
Chlorzoxazone 6-hydroxylation25–2,9771916.170.8371-165 0.4810.7441-160
(2E1)
DextromethorphanN-demethylation19–20589.450.2260.3920.200
(3A4)
Midazolam 1′-hydroxylation504–12,0575287.450.0660.5520.054
(3A4/5)

  • ↵1-a  P450-marker activities are expressed as pmol · mg protein−1 · min−1.

  • ↵1-b  PL-PHOS and PL-RAD formation are expressed as nmol 14C · mg PL−1.

  • ↵1-150  p < 0.05;

  • ↵1-160  p< 0.01;

  • ↵1-165  p < 0.001.