Production of Alkaline Enzymes by Alkalophilic Microorganisms Part III

Abstract

A crystalline alkaline protease was prepared from Bacillus No. 221 isolated from soil. The characteristic point of this microorganism is especially good growth in alkaline media. The enzyme was most active at pH 11.5 12 towards casein and was stable at pH values from 4 to 11 on 10 min incubation at 60°C. Calcium ion was effective to stabilize the enzyme especially at higher temperatures. The enzyme was completely inactivated by DFP and urea, but not affected by sulfhydryl reagent, EDTA, SLS, and DBS. The specific activity of the enzyme towards casein was about 18,000 unit/mg, and the isoelectric point was higher than pH 9.4. The molecular weight and sedimentation constant was approximately 30,000 and 3.5 S respectively, and N-terminal of the enzyme was identified to be alanine. The results indicate that the No. 221 alkaline protease is different from those of alkaline proteases of Bacillus subtilis.