Fig. 4.

SDS-PAGE image of step 3, optimization of additives concentrations to make TEV-protease more soluble after extraction. T" and S" show total and soluble samples, respectively. T"4 and S"4 are protein band extracts that their lysis buffer was designed by RSM method (Table 8), T"5 and S"5 are protein bands extracts that its lysis buffer was designed by Plackett-Burman method. Numbers 6, 7 and 8 show protein extraction in the presence of lysis buffer without additives, BL21 bacteria without TEV-protease genome, and extraction of protein in the presence of PBS as lysis buffer, respectively. SDS-PAGE, Sodium dodecyl sulfate-polyacrylamide gel electrophoresis; RSM, response surface methodology; TEV, Tobacco etch virus protease