Table 3

Effect of acetone on tolbutamide hydroxylation in HL microsomes and in the CYP2C9-reconstituted system

Kinetic ParameterAcetone Concentration
024
HL Microsomes
%
V max (pmol · min−1 · mg protein−1)466  (21)3-150 653  (34)667  (43)
K mM)135  (18)123  (18)104  (21)
CLmet(V max/K m) (μl · min−1 · mg protein−1)3.55.36.4
% change in CL relative to 0% solvent+51+83
RECO CYP2C9 System
V max (nmol · min−1 · nmol P-450−1)4.7  (0.2)7.2  (0.3)11.0  (1)
K mM)115.0  (16)99.0  (14)141.0  (37)
CLmet(V max/K m) (μl · min−1 · nmol P-450−1)40.972.778.0
% change in CL relative to 0% solvent+77+91
  • 3-150  Values in parentheses are nonlinear regression standard error.