Table 1 Expression and activity of PschSOD in recombinant BL21 cells with variable parameters
A: Temperature optimization for IPTG induced bacterial expression of PschSOD | |||||
|---|---|---|---|---|---|
While monitoring effect of temperature, Cu or Zn was not added in the growth media during induction period | |||||
Induction temperature (°C) | Induction period (Hour) | Final cell density (g L−1) | Quantity of protein# (mg L−1) | SOD activity mg−1 of crude protein | SOD activity mg−1 of purified proteinψ |
37 | 5 | 5 | 2.8 | 110 | 5,000-8,000 |
37 | 20 | 8 | 3.0 | 109 | 5,000-8,000 |
18 | 5 | 3 | 1.4 | 117 | 5,000-8,000 |
18 | 20 | 4.5 | 3.2 | 118 | 5,000-8,000 |
B: Effect of Cu (CuSO 4 ) and Zn (ZnSO 4 ) supplementation on expression and activity of PschSOD at 18°C | |||||
Final concentration of CuSO4 (μM) | Final concentration of ZnSO4 (μM) | Final cell density (g L−1) | Quantity of protein# (mg L−1) | SOD activity mg−1 of crude protein | SOD activity mg−1 of purified proteinψ |
0 | 0 | 4.5-5.0 | 3.2 | 118 | 5,000-8,000 |
0 | 250 | 4.5-5.0 | 3.6 | 120 | 5,000-8,000 |
250 | 0 | 4.5-5.1 | 3.5 | 790 | 46,000-56,000 |
250 | 250 | 4.5-5.1 | 4.0 | 820 | 49,000-58,000 |