Table 2.

Properties of the pH-induced unfolding reactions in citrate vs. acetate buffer

	Citrate		Acetate
Protein	pHm	ΔGNI	pHm	ΔGNI
WT	4.7	4.8	4.4	7.0
H24V/H119F	3.5*	7.2	3.2†	8.2
H36Q	n.d.	n.d.	5.3	5.3

Determined at 4.5°C in either 10 mM acetate or 2 mM citrate, 30 mM NaCl buffer. pH_m is the pH midpoint of the unfolding transition monitored by the final fluorescence values obtained in unfolding/refolding experiments, as in Fig. 4 A and B. ΔG_NI is the Gibbs energy difference between the native and molten globule forms at pH 9, in kcal/mol, computed from the values of k_u and k_f used to fit the curve of log k_obs vs. pH. 

^*A lower value than the one given here is obtained if the baseline found for the WT protein is used.