Table 3.

Thermodynamic parameters for imidazole binding to Cytc as a function of GdnHCl at I = 1.25 M, pH 7 and 25 °C.

Parameter	[GdnHCl] (M)	Protein
		Horse Heart Cytc	K72A/K72A/K79A iso-1-Cytc
K Im,Amp a	0	17 ± 2	570 ± 430
(M)	0.25	20 ± 2	720 ± 490
	0.50	25 ± 3	1000 ± 760
ΔG°′Imb	0	−1.68± 0.06	−3.7 ± 0.5
(kcal/mol)	0.25	−1.78 ± 0.06	−3.9 ± 0.4
	0.50	−1.90 ± 0.07	−4.1 ± 0.5

^aK_Im,Amp is the apparent binding constant for Im derived from kinetic amplitude data. Error is the standard error reported by SigmaPlot for fits to eq S2 in Fig. S5.

^bError is propagated from the error in K_Im,Amp.