title: A novel alkaline serine protease with fibrinolytic activity from the polychaete, Neanthes japonica.
abstract: A new protease named NJP with fibrinolytic activity was isolated from Neanthes japonica (Izuka), by a combination of ammonium sulfate fractionation, hydrophobic chromatography, ion-exchange chromatography and gel filtration. The molecular mass of NJP was approximately 28.6-33.5kDa as estimated by MALDI-TOF mass spectrometry and SDS-PAGE, which revealed a monomeric form of the protease. The isoelectric point of NJP determined by 2-DE was 9.2. NJP was stable in the range of pH 7.0-11.0 with a maximum enzymatic activity at 40°C and pH 9.0. The hydrolyzing activity of NJP on fibrinogen started from the Aα-chain, followed by the Bβ-chain, and the γ-chain at last. NJP had also a higher specificity for the chromogenic substrate S-2238 for thrombin. NJP activity was completely inhibited by PMSF. Analysis of partial amino acid sequences showed that NJP had very low homology with other known fibrinolytic enzymes. These results indicate that NJP is a novel alkaline thrombin-like serine protease. Thus NJP may have potential applications in the prevention and treatment of thrombosis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Norman Bethune College of Medicine, Jilin University, 126 Xinmin Street, Changchun, Jilin, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Wang
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Deng
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Ge
authors.forename: Qiqing
authors.initials: Q
authors.lastname: Bo
authors.forename: Jiankai
authors.initials: J
authors.lastname: Liu
authors.forename: Jiayue
authors.initials: J
authors.lastname: Cui
authors.forename: Xi
authors.initials: X
authors.lastname: Jiang
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Lianzhi
authors.initials: L
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Hong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005340:Fibrinogen / Q000378:metabolism; D005342:Fibrinolysis; D005343:Fibrinolytic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D011077:Polychaeta / Q000201:enzymology*; D057057:Serine Proteases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
chemical_list: D005343:Fibrinolytic Agents; D005340:Fibrinogen; D057057:Serine Proteases