Table 5

Parameters generated from a kinetic model for the interaction of diclofenac and quinidine with CYP3A45-a

μM nmol/min/nmol
Quinidine 3-hydroxylation1.3  ± 0.263.3  ± 9.6 5.8 ± 0.30.6 ± 0.41
(V maxQ)(α)
Diclofenac 5-hydroxylation1.4  ± 0.254.2  ± 4.510.5 ± 1.55.9 ± 0.82
(V maxD)(β)
  • 5-a  The kinetic model is shown in Fig. 2 and equations are described under Experimental Procedures.

  • 5-b  VmaxQ andVmaxD are the maximum velocities for the formation of 3-hydroxyquinidine and 5-hydroxydiclofenac, respectively;KS1 is the dissociation constant for EES1 and KS2 for EES2; α and β are the factors by whichVmax values increase (or decrease) when the second substrate is included in the interaction with the enzyme. Data are presented as mean ± S.E.