Table 2.

Substrate and product binding parameters to P450 11B2 in the presence of adrenodoxin and lipid

Ligand	Kd	kon	koff
	μm	μm−1 s−1	s−1
11-Deoxycorticosterone	0.016 ± 0.004a	4.20 ± 0.04b	0.07 ± 0.02c
Corticosterone	2.1 ± 0.3a	1.63 ± 0.02b	3.4 ± 0.4c
18-OH corticosterone	32 ± 6d	–e	–e
Aldosterone	70 ± 20d	–e	–e

^a Reported values for K_d come from quadratic fits to the data shown in Fig. 6, A and B.

^b Reported values for k_on are from nonlinear fits to the data in Fig. 7. See text for details.

^c Values calculated from K_d and k_on assuming k_off = K_d·k_on.

^d Reported values for K_d come from quadratic fits to the competition titration data in Fig. 6, C and D, which yields an apparent K_d that can be used to calculate the real K_d. See text for details.

^e Lack of significant spectral change upon binding prevented determination of these values.