TABLE 3

Kinetic parameters for dihydrodiol formation in reactions with compounds 4–7, 15, and 18a

CompoundHuman Recombinant mEHHLM without NADPH
KmVmaxVmax/KmKmVmaxVmax/Km
µMnmol/min/mgµMnmol/min/mg
467 ± 1017 ± 10.2627 ± 51.7 ± 0.10.06
547 (43, 59)17 (17, 17)0.3626 ± 61.7 ± 0.10.07
689 ± 1422 ± 20.2428 ± 86.6 ± 0.70.27
750 ± 735 ± 20.6951 (48, 56)16 (15, 16)0.31
15bbb352 (239, 695)0.9 (0.8, 1.4)0.003
18684 (650, 722)2.8 (2.7, 3.0)0.004139 (119, 165)0.4 (0.3, 0.4)0.003
cSOc14157047–2517–522.1–2.5
SOdeee40–30010–250.05–0.4
  • SO, styrene oxide.

  • a Values are the mean of triplicates ± S.E., except for compounds 5, 15, and 18 incubated with recombinant mEH and compounds 7, 15, and 18 incubated with HLMs, for which the duplicate averages (replicate 1, replicate 2) are reported. Product formation was linear with respect to time and enzyme concentration.

  • b Kinetic parameters could not be estimated since the velocity remained linear within the substrate concentration range chosen.

  • c Values are from Kitteringham et al. (1996), Hosagrahara et al. (2004), and Morisseau et al. (2011).

  • d Values are from Seidegård and DePierre (1980), Pacifici et al. (1986), and Eugster et al. (1991).

  • e Not tested