FIGURE 3.

Western blotting analysis of the cells with high or low β-galactosidase activity in the R1 population. A, 5 × 10⁶ cells induced 5.5 h with IPTG were first gated by flow cytometry according to the equal intensity of red fluorescence to ensure an identical expression level of recombinant proteins and then were sorted into two populations according to the intensity of green fluorescence. B, these two sorted populations, the high activity population and low activity population, were then collected and treated by ultrasonication followed by centrifugation. The supernatants and pellets of centrifugation were analyzed by Western blotting. Lysates from equal numbers of both cell population were loaded for Western blotting analysis.