title: A novel fibrinolytic serine protease from the polychaete Nereis (Neanthes) virens (Sars): purification and characterization.
abstract: A novel fibrinolytic serine protease has been identified and purified to homogeneity from the coelomic fluid of polychaete Nereis (Neanthes) virens (Sars), and named N-V protease. N-V protease is a 29kDa single chain protein with an isoelectric point of pH 4.5. It hydrolyzes Aalpha-chain of fibrinogen with a high efficiency, and the Bbeta- and gamma-chains (Aalpha>Bbeta>gamma) with a lower efficiency. The proteolytic activity peaks at pH 7.8 is 45 degrees C. The activity is completely inhibited by serine protease inhibitors DFP (I(50)=5.8 x 10(-4)M) and PMSF (I(50)=5.5 x 10(-2)M), and almost completely by TLCK (I(50)=7.7 x 10(-1) M). But aprotinin, elastinal, SBTI, benzamidine, PCMB, EDTA, EGTA, iodoacetate, E64, and beta-mercaptoethanol have no effect on the protease activity. Therefore, N-V protease is identified as a serine protease. The primary amino acid sequence of N-V protease was determined by mass spectrometry (N-V protease, No. P83433). According to the MALDI-TOF MS analysis, there is no existing protein in the NCBI Non-redundant Protein Sequence Database that matches the N-V protease sequence. Therefore, N-V protease is a novel and special protein in N. virens. Furthermore, we have successfully established an expression cDNA library from the whole body of N. virens (data not shown).
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Jilin University, Changchun 130021, China.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jiayue
authors.initials: J
authors.lastname: Cui
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Yanpin
authors.initials: Y
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Hong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D015723:Gene Library; D008969:Molecular Sequence Data; D011077:Polychaeta / Q000201:enzymology* / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D012697:Serine Endopeptidases