A novel fibrinolytic serine protease from the polychaete Nereis (Neanthes) virens (Sars): purification and characterization.

Yunlong Zhang, Jiayue Cui, Rui Zhang, Yanpin Wang, Min Hong

Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Jilin University, Changchun 130021, China.

Biochimie 2007 Jan

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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).

Citation

Yunlong Zhang, Jiayue Cui, Rui Zhang, Yanpin Wang, Min Hong. A novel fibrinolytic serine protease from the polychaete Nereis (Neanthes) virens (Sars): purification and characterization. Biochimie. 2007 Jan;89(1):93-103