title: Eisenia fetida protease-III-1 functions in both fibrinolysis and fibrogenesis.
abstract: The fibrinolytic function of earthworm protease-III-1 (Ef P-III-1) has been studied in recent years. Here, we found that Ef P-III-1 acted not only in fibrinogenolysis, but also in fibrogenesis. We have used Ef P-III-1 to hydrolyze fibrinogen, and to activate plasminogen and prothrombin. Based on the N-terminal sequences of the hydrolytic fragments, Ef P-III-1 was showed to specifically recognize the carboxylic sites of arginine and lysine. Analyses by fibrinogenolysis mapping and amino acid sequencing revealed that the isozyme could cleave the alpha, beta, and gamma chains of fibrinogen, showing a high alpha-fibrinogenase, moderate beta-fibrinogenase, and low gamma-fibrinogenase activities. Interestingly, Ef P-III-1 activated plasminogen and released active plasmin, suggesting a tPA-like function. Furthermore, Ef P-III-1 showed a factor Xa-like function on prothrombin, producing alpha-thrombin. The function in both activating prothrombin and catalyzing fibrinogenolysis suggests that Ef P-III-1 may play a role in the balance between procoagulation and anticoagulation.
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Baiao Pharmaceuticals Beijing C.L., Chinese Academy of Sciences, Chao Yang District, Beijing 100101, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Rong
authors.initials: R
authors.lastname: Pan
authors.forename: Jian
authors.initials: J
authors.lastname: He
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Dong-Feng
authors.initials: DF
authors.lastname: Li
authors.forename: Rong-Qiao
authors.initials: RQ
authors.lastname: He