Preparation and identification of a novel fibrinolytic enzyme FS33 from Bacillus subtilis DC_(33)

The method of purifying a novel fibrinolytic enzyme subtilisin FS33 by gel chromography was investigated in this paper.The crude enzyme produced by Bacillus subtilis DC33 was precipitated by 30%～65% saturation of(NH4)2SO4,and the protein collected by centrifugation(10000×g,15min) was applied to chromatographic procedures including hydrophobic chromatography,anion exchange and gel filtration chromatography.The finally eluted proteins by Sephadex G-50 gel filtration were subjected to SDS-PAGE.Under these conditions,the purified rate and the recovery of final enzyme were 36.6 fold and 13.0%,respectively.The specific activity of the fibrinolytic enzyme was 15495U/mg,and only one band was observed in the purified sample under reducing or non-reducing conditions.The molecular mass was estimated to be approximately 30kDa.The higher fibrinolytic activities of the purified enzyme band were observed on the plasminogen-free fibrin plate.