Table 2.

Summary of association and dissociation rates for Ca²⁺/CaM-CaMKI peptide

Condition	kon (M−1 s−1)	koff (k1) (s−1)	koff (k2) (s−1)	Kd (M)a
None	6.3 × 108 ± 9.5 × 106	1.05 ± 0.13	0.11 ± 0.012	1.7 × 10−9
5% ficoll-70	4.7 × 108 ± 2.0 × 106	0.79 ± 0.10	0.09 ± 0.008	1.69 × 10−9
10% ficoll-70	4.3 × 108 ± 3.3 × 107	0.75 ± 0.05	0.08 ± 0.01	1.75 × 10−9
15% ficoll-70	3.4 × 108 ± 1.0 × 106	0.67 ± 0.07	0.08 ± 0.01	2.00 × 10−9
5% dextran-10	6.19 × 108 ± 1.8 × 107	0.72 ± 0.095	0.07 ± 0.02	1.16 × 10−9
10% dextran-10	5.77 × 108 ± 1.1 × 107	0.69 ± 0.078	0.06 ± 0.01	1.20 × 10−9
15% dextran-10	3.74 × 108 ± 1.7 × 107	0.62 ± 0.072	0.06 ± 0.01	1.65 × 10−9
20% dextran-10	2.87 × 108 ± 1.6 × 107	0.49 ± 0.067	0.02 ± 0.002	1.72 × 10−9
5% sucrose	4.52 × 108 ± 4.0 × 106	0.77 ± 0.11	0.10 ± 0.02	1.69 × 10−9
10% sucrose	4.19 × 108 ± 9.5 × 106	0.80 ± 0.10	0.12 ± 0.01	1.90 × 10−9
15% sucrose	3.81 × 108 ± 8.0 × 106	0.64 ± 0.07	0.08 ± 0.004	1.69 × 10−9
20% sucrose	2.63 × 108 ± 5.0 × 105	0.43 ± 0.03	0.05 ± 0.003	1.62 × 10−9

Averages of measured on-rates and off-rates are reported for volume exclusion (n = 2). Double-exponential equations were required to fit dissociation curves, where k₁ rates account for ∼90% of the change in amplitude and k₂ rates represent the remaining ∼10%.

^aEstimates of dissociation constants were calculated using the relationship K_d = k₁/k_on.