PRODUCTION OF 2 PROTEOLYTIC ENZYMES BY A TRANSFORMABLE STRAIN OF BACILLUS SUBTILIS

A transformable strain of Bacillus subtilis has been shown to produce two distinct proteolytic enzymes in its culture medium, and in addition a third form that appears to be due to aggregation of one of the enzymes during salt concentration. The protease which appears late in the growth period can be isolated by binding to DEAE-cellulose at high pH, and has, in addition to proteolytic activity on casein, the ability to cleave benzoyltyrosine ethyl ester (BTEE). The second enzyme, which appears earlier in the growth of a culture, does not bind to DEAE-cellulose and cannot hydrolyze BTEE to any appreciable extent. Both enzymes have been purified by ion-exchange chromatography and gel filtration, and show single bands on acrylamide gel and cellulose acetate electrophoresis. Characterization studies show that the two enzymes have similar properties with regard to heat inactivation, response to inhibitors and metal ions, and pH optima and stabilities, and have slightly different molecular weights. The enzymes differ markedly, however, in their electrophoretic mobilities, precipitability by ammonium sulfate and amino acid compositions. © 1968.