The Cry1Ab/Ac protein was dissolved in 20 mM tris–HCl and 5 mM EDTA buffer at a concentration of 0.1 mg mL−1 in 1.5 mL microcentrifuge tubes. They were tested for stability at temperature of 100 °C for periods of 10, 30, and 60 min. The assay was terminated by placing the sample tubes on ice, and adding SDS-sample buffer (50 mM tris–Cl, 8% sucrose, 2% SDS, with 5% 2-mercaptoethanol, and 0.02% bromophenol blue). Control samples of a 0 min incubation of the protein (kept at 4 °C) were also prepared (Hérouet et al., 2005). The resulting proteins were analyzed by SDS–PAGE and Western Blot.