Table 2

Summary of average (standard error) enzyme kinetic parameters for fluoxetine N-demethylation in recombinant heterologously expressed human CYP enzymes^2-a

Enzyme	(R)-Fluoxetine		(S)-Fluoxetine		Racemic Fluoxetine
Enzyme	K_M	V_max	V_max/K_M	K_M	V_max	V_max/K_M	K_M	V_max	V_max/K_M
CYP1A2	359 (76)	26.9 (2.4)	0.075	474 (102)	33.4 (3.3)	0.071	501 (64)	37.9 (2.2)	0.076
CYP2B6	126 (19)	1.19 (0.11)	0.010	546^2-b (370)	2.55 (0.53)	0.005	246 (71)	1.64 (0.38)	0.007
CYP2C9	13.6 (1.6)	17.0 (0.7)	1.24	184^2-b (52)	45.6 (21.9)	0.248	30.7 (3.2)	19.6 (1.6)	0.638
CYP2C19	154 (10)	41.2 (0.5)	0.275	251 (45)	46.6 (2.0)	0.186	172 (25)	39.0 (1.1)	0.227
CYP2D6	1.42 (0.27)	4.13 (0.21)	2.91	3.81 (0.41)	8.54 (0.33)	2.24	2.20 (0.31)	6.32 (0.25)	2.87
CYP3A4	33.5 (2.5)	10.6 (0.7)	0.316	33.5 (1.9)	10.6 (0.5)	0.316	19.3 (1.8)	8.36 (0.49)	0.433
CYP3A5	79.8 (8.6)	9.36 (0.50)	0.117	92.4 (6.5)	9.06 (0.35)	0.098	89.4 (22.3)	8.67 (1.20)	0.097

↵2-a Units areK_M (μM); V_max(pmol/min/pmol of CYP);V_max/K_M (μl/min/pmol of CYP).
↵2-b Represents an estimate;K_M for CYP2B6 and CYP2C9 andS-fluoxetine exceeded the highest concentration tested.