Because of its stringent sequence specificity, tobacco etch virus (TEV) protease emerges as a useful reagent with wide application in the cleavage of recombinant fusion proteins. However, the Solubility of TEV protease expressed in Escherichia coli is extremely low. In the present study, we introduced a more efficient system to improve and facilitate the soluble production of TEV protease in E. Coli. Optimal expression of soluble His6-TEV was achieved by examining the contribution of chaperone co-expression and lower temperature fermentation. When further purified by Ni2+ affinity chromatography, 65 mg of His6-TEV was isolated with purity over 95% from I L of culture. The enzyme activity of His6-TEV was generally characterized by using GST-EGFP and His6-L-TNF fusion protein as substrates, which contained a TEV cleavage site between two moieties. (c) 2006 Elsevier Inc. All rights reserved.