Purification and properties of a neutral protease produced by Lactobacillus brevis

Abstract

A proteolytic enzyme was produced by a strain of Lactobacillus brevis isolated from an oriental beverage. The enzyme was extracted and purified 50-fold by gel filtration and ion-exchange chromatography. The optimum pH for the enzyme was 7.0, the optimum temperature 35°C and the molecular weight 34,674 Da. Furthermore, the enzyme was stimulated by cations including Ca2+, Mg2+, Na+ and K+ and inhibited by Zn2+ and Co2+ ions. Other inhibitors were EDTA, ascorbic acid and citric acid. The enzyme is probably a neutral metalloprotease.