Table 2

Kinetic parameters of product formation from MDMA and MeAmp in microsomes from yeast expressing CYP2D6

SubstrateReactionsKm (μM)Vmax (nmol/min/nmol P450)Vmax/Km N
(+) MDMADemethylenation1.4  ± 0.22-a 7.0  ± 0.142-a 5.1  ± 0.72-a 43
(−) MDMADemethylenation3.2  ± 0.29.0  ± 0.132.8  ± 0.234
(+) MeAmp N-demethylation25.8  ± 3.52-b 1.3  ± 0.042-a 0.05  ± 0.012-a 21
4-hydroxylation12.3  ± 1.32-a 0.62  ± 0.012-a 0.05  ± 0.012-a 21
(−) MeAmp N-demethylation53.5  ± 6.00.96  ± 0.040.02  ± 0.0016
4-hydroxylation32.0  ± 3.51.00  ± 0.030.03  ± 0.0016

  • N, data points used for nonlinear regression analysis. Values are presented ± asymptotic SD.

  • ↵2-a (+) vs (−), p < 0.01.

  • ↵2-b (+) vs (−), p < 0.05.