title: Purification and partial characterizations of coagulant protein FIa from Daboia russelli siamensis (Myanmar) venom.
abstract: OBJECTIVE
  To purify and characterize the coagulant protein FIa from Daboia russelli siamensis (Myanmar) venom.
  
  
  METHODS
  FIa was purified from Daboia russelli siamensis (Myanmar) venom by ion-exchange chromatography on CM-Sephadex C-50, and gel filtration on Sephadex G-75 and a Superdex 75 column. The hemostatic activity of FIa was determined by the method of Williams and Esnouf. The specific chromogenic substrates were used respectively to determine the activation of factor X and prothrombin. The fibrinogen-clotting activity of FIa was determined by the method of Gao et al. Normal saline was used as a negative control while factor Xa and thrombin were used as positive controls, respectively.
  
  
  RESULTS
  FIa, a coagulant protein, was achieved by ion-exchange chromatography and gel filtration with a molecular weight of 34,479 and an isoelectric point of 7.2. FIa was shown to have strong hemostatic activity. The hemostatic activity of 0.5 mg FIa was equal to that of 1.5625 u thrombin. FIa primarily activated factor X, however, had no influence on prothrombin, nor did it cleave or clot fibrinogen.
  
  
  CONCLUSIONS
  FIa is a factor X-activating enzyme, which could activate factor X to factor Xa, but has no effect on prothrombin and fibrinogen.
authors: Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, Guangzhou 510080, China.
authors: Huan-Huan
authors: HH
authors: Sun
authors: Qi
authors: Q
authors: Chen
authors: Xi
authors: X
authors: Lin
authors: Jia-Shu
authors: JS
authors: Chen
authors: Peng-Xin
authors: PX
authors: Qiu
authors: Guang-Mei
authors: GM
authors: Yan
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003029:Coagulants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D005170:Factor X / Q000378:metabolism; D006801:Humans; D007526:Isoelectric Point; D008666:Metalloendopeptidases / Q000302:isolation & purification*; D008970:Molecular Weight; D011516:Prothrombin / Q000378:metabolism; D014757:Viper Venoms / Q000737:chemistry* / Q000302:isolation & purification; D017819:Viperidae
chemical_list: D003029:Coagulants; C532396:Fla coagulant protein, Daboia ruselli; D014757:Viper Venoms; D011516:Prothrombin; D005170:Factor X; D008666:Metalloendopeptidases; C476775:factor X activator, Russell's viper