Optimization of the expression of reteplase in Escherichia coli

Reteplase is a segment of tissue plasminogen activator used for the removal of thrombi in blood vessels. In the present study the cloned reteplase gene was used for its expression in competent E. coli. The recombinant plasmid, pET15b/reteplase (rpET-BL21), was transformed into competent E. coli strain BL21 (DE3) cells. Overnight culture of the transformed bacteria was induced by the addition of isopropylthio-ß-Dgalactoside (IPTG) to the final concentrations of 0.25, 0.5, 1 and 1.5 mM. Also, the effects of different temperatures(25, 30, 37 and 39°C), shaking speeds (100, 170 and 190 rpm), and various glucose concentrations (0.25, 0.5, 0.75 and 1 mM) on the expression of reteplase were examined. Samples were analyzed by SDS-PAGE. Maximum amount of protein production was obtained by the addition of 1 mM IPTG at 37°C, 100 rpm of shaking speed in the absence of glucose.