Abstract:

In order to obtain pure fibrinolytic enzyme and reveal the enzymatic properties , a fibrinolytic enzyme-producing strain with high fibrinolytic activity was screened form Douchi , a traditional Chinese soybean food and was identified as Bαcillus subtilis. The mutant DC-12N8 of the strain was then processed in the following procedure:centrifugal sterilization , fractional sedimentation with ammonium sulfate , DEAEδepharose Fast Flow and CM-Seph-arose Fast Flow ion-exchange chromatography , Sephadex G-75 gel-filtration. Thus , a kind of fibrinolytic enzyme was purified from Douchi. As compared with the crude enzyme extraction , the specific activity of the purified en-zyme increases by 52. 6 folds with a recovery of 11. 7 % , and 4. 5 mg of active enzyme protein with an activity of 1. 18 mol/s can be obtained from 1 L of fermentation liquid. SDS-PAGE results show that the purified enzyme is a kind of single-train protein with a molecular mass of 28 ku.

Key words: fibrinolytic enzyme, identification, purification