title: Purification and Characterization of the Fibrinolytic Enzyme(eFE-D) from Earthworm Eisenia folelide.
abstract: The fibrinolytic enzyme eFE-D was isolated and purified from earthworm Elsenia folelide by gel-filtration on Sephacryle S-200, ion-exchange chromatography on DEAE-Sepharose Fast Flow and hydrophobic chromatography on Phenyle-Sepharose Fast Flow as detected by the fibrinolytic activity with a standard fibrin plate method. The most strong fibrinolytic component eFE-D not only hydrolyzed fibrin directly, but also activated the plasminogen to plasmin. Its apparent fibrinolytic value was equal to 2,800 UK IU per mg. Its molecular weight as estimated by SDS-PAGE and MS analysis was 29 kD and 24.849 kD respectively and its isoelectric point (pI) was 4.O. Fibrinolytic enzyme eFE-D was very thermostable with a single polypeptide chain. Studies with protease inhibitors indicated that eFE-D was a kind of serine protease. Its N-terminal amino acid sequence is M-I-G-G-T-N-A-S-P-G-E-F-P-W-Q-L-S-Q-Q-R. The result of amino acid composition analysis showed that the enzyme contained abundant amino acids of low molecular weight, but few aromatic and alkaline amino acids.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Bao-Dong
authors.initials: BD
authors.lastname: Xing
authors.forename: Shen-Min
authors.initials: SM
authors.lastname: Yin
authors.forename: Bing-Gen
authors.initials: BG
authors.lastname: Ru