Table 3.

Equilibrium thermodynamic parameters of urea- and GdnHCl-mediated LF unfolding.

Parameters	Urea			GdnHCl
	ZnLF	ApoLF	ApoLF+Zn2+	ZnLF	ApoLF
2 State model
$\mathrm{\Delta }{G}_{N\to U}^0$ (kcal mol−1)	10.1 (±0.4)	–	9.6 (±1.1)	7.8 (±0.7)	5.1 (±0.5)
$m_{N\to U}$ (kcal mol−1 M−1)	6.6 (±0.3)	–	5.7 (±0.8)	15.9 (±1.4)	10.0 (±1.4)
3 State model
$\mathrm{\Delta }{G}_{N\to I}^0$ (kcal mol−1)	–	6.0 (±0.6)	–	–	–
$m_{N\to I}$ (kcal mol−1 M−1)	–	4.4 (±0.3)	–	–	–

The parameters $\mathrm{\Delta }{G}^0$ and m were obtained by fitting the recorded fluorescence intensities (FI₃₃₃) after 24 h of incubation of the LF preparation indicated in the table with urea or GdnHCl to Eq. (1) (two-state model) or Eq. (2) (three-state model). Values represent the mean (±1 s.d.) of three independent experiments, and were calculated by averaging the parameters from each of the three unfolding profiles. The thermodynamic parameters describing the I→U transition (for urea-exposed apoLF only) have been omitted since the standard errors for these fitting parameters were too large (40–50%) to allow for their reliable estimation.