Table 2. Compound Binding to CYP46A1^a.

compd	Kd for substrate-free CYP46A1 (M)	calculated konb (M–1 s–1)	experimental koff (s–1)
cholesterol	9 × 10–9 c	1.3 × 106	0.012 ± 0.002
(S)-EFV	5 × 10–6 d ± 0.4 × 10–6	2.2 × 106	11.2 ± 0.9
rac-3	5 × 10–6 e ± 0.3 × 10–6	0.7 × 106	3.6 ± 0.2

^aExperimental data are presented as the mean ± SD of the measurements from the three independent experiments.

^bValues calculated from K_d and k_off assuming .

^cThis value comes from an apparent K_d of 80 nM ²⁰ after the correction for HPCD binding. See Experimental Section for details.

^dThis is the K_d value for titrations at 24 °C ²⁰ because the stopped-flow experiments were conducted at 23 °C.

^eThis is the K_d value for titrations at 24 °C determined in the present work in addition to the K_d value at 18 °C (Figure 3) as compared to rac-3, for the CYP46A1 active site binding and hence inhibition.