A Proteolytic Enzyme of Streptomyces Griseus

Purification of protease of bacteria or fungi has been reported by many investigators, but so far there is little information about the protease of Actinomycetes, a large family of microorganisms widely distributed in nature. Recently, it was found by .the authors that a strain of Streptomyces griseus which has been used for the industrial production of streptomycin excreted a remarkable amount of protease in the usual culture broth, together with streptomycin. The protease productivity of this strain was almost equal to that of excellent strains of Bacillus subtilis which have been used for industrial production of bacterial protease. Up to date, however, the existence of this enzyme has not been known, and the enzyme has been completely destroyed under the. severe condition during conventional procedures for the purification of streptomycin. Thus, it was attempted to utilize this enzyme as a by-product of streptomycin production in order to reduce the cost of manufacturing this antibiotic. After many trials, this protease could be separated from streptomycin by a salting out procedure and was highly purified by the following procedures ; resin column treatment, salting out and acetone precipitation. Crystalline preparations of the protease are obtainable through these procedures. This enzyme was named as “Streptomyces protease G” by the authors. In this paper is presented the method for separation and purification of this protease.