Table 5

Kinetic parameters of MOM-hydroxylated metabolites formation by human liver microsomes and expressed CYP3A4

Mb-3Mb-5Mb-9aMb-13
Human liver microsomes K M(μM)16.3 ± 4.35-a 17.8 ± 1.546.6 ± 5.611.3 ± 1.2
V max (pmol/min/mg protein)699 ± 2951410 ± 7872767 ± 13861588 ± 897
V max/K M (μl/min/mg protein)45.3 ± 25.080.4 ± 45.661.7 ± 37.6141.3 ± 79.1
Insect cell microsomes K M(μM)15.921.934.617.2
Expressed CYP3A45-b V max(pmol/min/pmolCYP)1.442.937.283.76
V max/KM(μl/min/pmolCYP)0.09060.13380.21040.2186

  • ↵5-a Each value using human liver microsomes was expressed as the mean ± S.D. (n = 5).

  • ↵5-b Insect cell microsomes containing cDNA-expressed CYP3A4, NADPH-CYP reductase, and cytochrome b5.