Fig. 3

(A) Induced expression of the amyS gene in the E. coli BL21(DE3) strain. a represents commercial α-amylase (Ruibio, Germany); (b) represents unpurified AmyS protein; (c) represents purified AmyS protein; (d) represents purified protein diluted twice; (e) represents purified protein diluted threefold; (f) represents purified protein diluted fourfold; (g) represents purified protein diluted fivefold. B Determination of the enzymatic activity of AmyS protein. Five microliters of AmyS protein with different concentrations was harvested, inoculated on LB solid medium containing 1% starch (w/v), cultured at 30 °C for 2 d and fumigated with iodine for 5 min. The size of the white transparent circle represents the enzymatic activity of the AmyS protein. a represents the commercial α-amylase; (b) represents purified AmyS protein; (c) represents the purified protein diluted twice; (d) represents the purified protein diluted threefold; (e) represents the purified protein diluted fourfold; (f) represents the purified protein diluted fivefold