7.6.2.2 | most suitable component for maintaining hMDR1 activity is PIPES, rather than citric acid, imidazole, MES, or MOPS. Optimal pH for stabilizing the recombinant enzyme protein during purification is pH 6.5. Addition of CHS preserves 90% of the activity at 25°C after 1 day, whereas little or no activity remains without CHS. The specific ATPase activity is completely diminished after 2 h at 37°C, but 75% of the ATPase activity remains after 24 h at 10°C |