关键词: Nereis virens, 纤溶酶, 纤维蛋白水解活性, 丝氨酸内肽酶类

Abstract: To detect the partial molecular characteristics of a novel fibrinolytic protease from the coelomic fluid of Nereis virens identified and purified to homogeneity. Methods The fibrinolytic protease was purified with anion and cation exchange chromatography and gel filtration chromatography. The identification of fibrinolytic activity and active distributed curve had been assessed by method of fibrin plate. Its apparent molecular weight and isoelectric point were analysed by two-dimensional gel electrophoresis (2-DE). The effects of several protease inhibitors on the protease activity were examined, and its protease type was identified. Results A novel and single chain fibrinolytic protease was purified effectively. Its apparent molecular weight and isoelectric point were 29 000 and 4.5, respectively. The proteolytic activity peaked at pH 7.8 and 45℃. The protease was completely inhibited by DFP and PMSF, assessin g as a serine protease. Conclusion From the coelomic fluid of Nereis virens, a novel and single chain serine protease with more strong fibrinolytic activity is discovered. The fibrinolytic protease has a medical value for preventing and treating thrombosis.

Key words: Nereis virens, plasmin, fibrinolytic activity, serine endopeptidases