A new semi-alkaline proteinase produced by Streptomyces cinereoruber.

Semi-alkaline proteinases having optimum pH between 8 and 9 of Streptomyces origin. have been reported as products of Streptomyces erythreus,3)Streptomyces fradiae4)and Streptomyces madurae.5)The proteolytic activity of all of the above semi-alkaline proteinases can be inactivated by addition of diisopropylfluorophosphate.We have recently isolated a new semi-alkaline proteinase from the cultured-broth of Streptomyces H 55SY 7 which was isolated from a soil sample collected at Kochi prefecture and identified as Streptomyces cinereoruber.6) The proteolytic activity of the new semi-alkaline proteinase is not inactivated by addition of diisopropylfluorophosphate,but inactivated by addition of ethylenediaminetetraacetate. Production,isolation,purification and enzymatic characteristics of the proteinase are presented in this paper. The semi-alkaline proteinase was produced by cultivation of Streptomyces H 55-SY 7 in shaking flasks containing a medium composed of starch,glucose,soy bean meal,yeast extract and various inorganic salts on a reciprocal shaker.The proteinase was precipitated from the broth filtrate by saturation with ammonium sulfate and the crude enzyme mixture was reprecipitated by addition of cold acetone after dialysis against water.The enzyme was purified by gradient column chromatography on DEAE-cellulose after gel filtration