N-terminal deletion of Tk1689, a subtilisin-like serine protease from Thermococcus kodakaraensis, copes with its cytotoxicity in Escherichia coli.

Tk1689, a subtilisin-like serine protease from Thermococcus kodakaraensis, was found to be toxic to the host cells when produced in the pro-protein form (Pro-Tk1689) in Eschericia coli. Cytotoxic effect of Pro-Tk1689 was reduced when signal and pro-peptide both were removed and the protein was produced in the mature form (MP-Tk1689). The mature protein was produced in E. coli in the soluble form. Recombinant MP-Tk1689 was catalytically active and exhibited optimum activity at 55°C and pH 7. Specific activity of the enzyme was 700 U/mg. The enzyme displayed a half life of 80 min at 60°C.