%0 Journal Article %T Cloning, Expression and Activity Analysis of a Novel Fibrinolytic Serine Protease from Arenicola cristata Cloning, Expression and Activity Analysis of a Novel Fibrinolytic Serine Protease from Arenicola cristata %A ZHAO Chunling %A JU Jiyu %J 中国海洋大学学报(英文版) %D 2015 %X The full-length c DNA of a protease gene from a marine annelid Arenicola cristata was amplified through rapid amplification of c DNA ends technique and sequenced. The size of the c DNA was 936 bp in length, including an open reading frame encoding a polypeptide of 270 amino acid residues. The deduced amino acid sequnce consisted of pro- and mature sequences. The protease belonged to the serine protease family because it contained the highly conserved sequence GDSGGP. This protease was novel as it showed a low amino acid sequence similarity(< 40%) to other serine proteases. The gene encoding the active form of A. cristata serine protease was cloned and expressed in E. coli. Purified recombinant protease in a supernatant could dissolve an artificial fibrin plate with plasminogen-rich fibrin, whereas the plasminogen-free fibrin showed no clear zone caused by hydrolysis. This result suggested that the recombinant protease showed an indirect fibrinolytic activity of dissolving fibrin, and was probably a plasminogen activator. A rat model with venous thrombosis was established to demonstrate that the recombinant protease could also hydrolyze blood clot in vivo. Therefore, this recombinant protease may be used as a thrombolytic agent for thrombosis treatment. To our knowledge, this study is the first of reporting the fibrinolytic serine protease gene in A. cristata %U http://qdhb.cbpt.cnki.net/WKD/WebPublication/paperDigest.aspx?paperID=c6d7bbea-7ef7-4531-87e7-0f5f5f74dcac