Figure 3
SDS-PAGE analysis of isoamylase expression and purification in E. coli BL21 (DE3) and Rosetta (DE3).
(a)Lanes: M, markers; B, BL21 host; R, Rosetta host; S, the supernatant of the cell lysate of E. coli Rosetta; T, the cell lysate of E. coli Rosetta; P: pellets of the cell lysate of E. coli Rosetta; HT, the supernatant of the heat-treated cell lysate of E. coli Rosetta; and His, the purified isoamylase by using Ni-charged resins. Effect of pH on the isoamylase activity (b). Buffer concentration was 40 mM and 0.5 mM MgCl2: acetate buffer (pH 4–6) and phosphate buffer (pH 5–8). Data represent the mean ± S.D. from triplicate experiments. Effect of temperature on the isoamylase activities (c). Reaction conditions were 40 mM acetate buffer (pH 5.5) containing 0.5 mM MgCl2. Data represent the mean ± S.D. from triplicate experiments.
