Table 3.

Kinetic parameters for 1-methylimidazole binding into the Trp-191 cavity of the yCcP/MIM complex. ^a

pH	$K_A^{\mathit{app}}$ b (M−1)	KA2 (M−1)	k4 (M−1 s−1)
4.1	4.72	(2.94 ± 0.28) × 102	(1.55 ± 0.08) × 10−1
4.5	4.37	(9.19 ± 0.52) × 101	(2.49 ± 0.16) × 10−2
5.0	3.53	(1.74 ± 0.17) × 102	(2.72 ± 0.35) × 10−2
5.5	2.48	(1.73 ± 0.35) × 102	(1.14 ± 0.03) × 10−2
6.0	1.74	(2.64 ± 0.18) × 102	(1.60 ± 0.03) × 10−2
6.5	1.40	(2.13 ± 0.27) × 102	(1.26 ± 0.03) × 10−2
7.0	1.30	(2.13 ± 0.81) × 103	(9.21 ± 3.17) × 10−3
7.5	1.24	(4.52 ± 5.10) × 103	(5.48 ± 1.2) × 100

^aThe data in Fig. 7 were fit to Eq. 5 for the Extended Cavity Model – Scheme 2 in the text. Four of the parameters defined in Scheme 2 have fixed values, independent of pH: k₁ = 9.4 × 10⁻⁵ s⁻¹; k₋₁ = 2.3 × 10⁻³ s⁻¹; K₃ = 0.041. K_A1 varies with pH according to the relationship K_A1 = 0.04$K_A^{\mathit{app}}$.

^b$K_A^{\mathit{app}}$ was calculated from the best-fit line shown in Fig. 5.