Characterization of Proteinases Excreted by Bacillus subtilis Marburg Strain during Sporulation

Abstract

S ummary . This study has characterized 3 proteolytic enzymes during sporulation by Bacillus subtilis Marburg strain when grown in nutrient broth. A method of purification is described which permits the separation of 2 different proteinases: one belonging to the metal enzyme group and the other to the serine enzyme group. The third enzyme, probably an esterase, showed a high esterolytic activity, but only low proteolytic activity. Determination of the 3 enzymes in a mixture was accomplished by using specific substrates and inhibitors. They were excreted simultaneously between the end of the growth phase until the appearance of the prespores. During this entire period, 20% of the total proteolytic activity was due to the metal proteinase; 80% of the proteolytic activity and 15% of the esterolytic activity was due to the serine proteinase; 85% of the esterolytic activity was the result of the esterase. These findings will contribute to a more complete phenotypic characterization of those mutants of sporulation that appear to be involved in the production of extracellular hydrolytic enzymes.