Figure 4.

Thermal stability of human G6PD enzymes. (A) Thermal unfolding of WT G6PD and the mutants (0.8 mg/mL) in 25 mM NaPO₄ pH 7.4 was monitored by recording the change in CD signal at 222 nm at different temperatures ranging from 20 to 90 °C. The unfolded fraction of protein and the T_m (melting temperature midpoint of the transition values) (inset) were calculated as previously reported [22]; and (B) Thermal inactivation assays of WT G6PD and the mutants after incubation for 20 min at the indicated temperature. The T₅₀ (temperature where 50% of its original activity is retained) after incubation at different temperatures for 20 min is shown. In all cases, 200 ng of total protein was used. The assays were performed in duplicate; standard errors were lower than 5%.