Dear Sir. Concerning your issue about determination the inactivation methods for proteases . Protease assays for heat inactivation profiles of both purified enzymes and cell lysates were determined using the EnzCheck protease assay method. Dilutions of purified A9 protease were divided into six aliquots, each of which was treated to a 20-min inactivation at a di¡erent temperature. For comparative purposes, all activities were determined as relative percent activity, with 100% activity being regarded as the activity following treatment of the protease at 37 0C for 20 min. The average relative percent activity was determined from duplicates at each inactivation temperature. Protease activity was also measured in crude cell lysates. 10-ml cultures of E. coli or the psychrotrophs were grown to late exponential stage and collected by centrifugation. The pellets were resuspended in 400^600 Wl of 50 mM Tris, pH 7.5. Each suspension was placed in a cryotube containing 250 Wl 0.1-mm-diameter zirconium beads. Samples were shaken in a Mini Bead-beater (Biospec Products, Bartlesville, OK, USA) for two 40-s periods separated by a 3-min incubation on ice. The cellular extracts were subjected to centrifugation, and supernatants containing the soluble fraction of the cell lysates were moved to new tubes. I think the following below link may help you in your analysis:

http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6968.2001.tb10583.x/pdf

Thanks