Table 5

Kinetic parameters for product formation from BFC, BQ, and AMMC in HLM, RLM, or cDNA-expressed P450s

SubstrateEnzyme SourceModelKM orS50Vmax5-aHill Coefficient
(n)5-b
BFCHLM (0–2.5 μM)Hyperbola3.8  ± 0.6250  ± 27
BFCHLM (5–160 μM)Hill23  ± 21325  ± 511.4  ± 0.1
BFCCYP3A4Hill40  ± 2.558  ± 1.71.3  ± 0.1
BFCCYP3A5Hill33  ± 1.03.1  ± 0.11.5  ± 0.1
BFCCYP1A2Hyperbola18  ± 0.36.1  ± 0.05
BFCCYP2C19Hyperbola26  ± 20.53  ± 0.01
BQHLM (0–320 μM)Hyperbola/ S 50 = 70  ± 2.5 V 1 4892  ± 19292.7  ± 0.7
Hill (eq. 1) K M = 28  ± 45 V 2 1714  ± 2195
BQHLM (0–5 μM)Hyperbola6.7  ± 22539  ± 1151
BQHLM (10–320 μM)Hill62  ± 46807  ± 2311.8  ± 0.2
BQCYP3A4Hill22  ± 0.8226  ± 0.481.9  ± 0.1
BQCYP3A5Hill52  ± 1.810  ± 0.21.5  ± 0.1
BQCYP1A2Hyperbola53  ± 5.54.4  ± 0.15
AMMCRLMHyperbola7.4  ± 0.41440  ± 24
AMMCCYP2D2Hyperbola4.6  ± 1.624  ± 2.9
  • 5-a  Expressed in units of picomoles per minute per milligram (with liver microsomes) or picomoles per minute per picomole (with Supersomes).

  • 5-b  Number of ligand binding sites bound by the substrate.

  • 5-c  Parameter estimate ±S.E. of the parameter estimate.