FIG. 2.
Heat-induced unfolding transitions of the wild-type α-amylase (•) and the recombinant enzyme produced at 18°C (○). The fraction of protein in the unfolded state (fU) was calculated as follows: fU = (yF − y)/(yF − yU), where yF and yU are the fluorescence intensities of the native and the fully unfolded states, respectively, and y is the fluorescence intensity at a given temperature. The inset shows a plot of ΔG as a function of the temperature around the melting point (Tm), where ΔG = 0.