Purification and characterization of an alkaline protease from Pseudomonasaeruginosa MN1

An alkaline protease produced by Pseudomonas aeruginosa MN1, isolated from an alkaline tannery waste water, was purified and characterized. The enzyme was purified 25-fold by gel filtration and ion exchange chromatography to a specific activity of 82350 U mg(-1). The molecular weight of the enzyme w as estimated to be 32000 daltons. The optimum pH and temperature for the pr oteolytic activity were pH 8.00 and 60 degrees C, respectively. Enzyme acti vity was inhibited by EDTA suggesting that the preparation contains a metal loprotease. Enzyme activity was strongly inhibited by Zn2+, Cu2+ and Hg2+ ( 5 mM), while Ca2+ and Mn2+ resulted in partial inhibition. The enzyme is di fferent from other Pseudomonas aeruginosa alkaline proteases in its stabili ty at high temperature; it retained more than 90% and 66% of the initial ac tivity after 15 and 120 min incubation at 60 degrees C.