Abstract
Plant FtsH protease is a membrane-associated protease localized on the thylakoid membrane. Its function is to remove a damaged protein from large protein complex. Major physiological substrate of this protease is D1 protein whose subunit plays a key role in the photosystem II. Knockout mutants of this protease shows variegated phenotype in Arabidopsis, therefore physiological function of this protease is to maintenance the chloroplast proteins. In this study, we constructed over-expression system of protease domain in FtsH protease from tobacco. Protein was produced as inclusion body, though these were possible to be activated by urea mediated refolding. Expressed protein showed protease activity on FITC (fluorescein isothiocyanate)-labeled casein. FITC-BSA (bovine serum albumin) did not digested by this protease, thus substrate specificity was detected on this protease. Biochemical study revealed that protease activity was enhanced by higher concentration of magnesium ion. Optimum pH was determined as alkalescent condition.
