Purification, Biochemical Properties, and Activities of a Novel Factor X Activator (F V e-1 ) from Daboia Russelli Siamensis ( Myanmar ) Venom / 中山大学学报(医学科学版)

ABSTRACT

[Objective] To purify and characterize a novel factor X activator,Fve-1 from Daboia russelli siamensis (Myanmar) venom.[ Methods]F V e-1 was purified by ion-exchange chromatography and gel filtration.The hemostatic activity of F V e-1 was determined based on chromogenic substrates.The fibrinogen-clotting activity of F V e-1 was also determined.Thermal stability, pH stability,enzyme activity,and inhibition of F V e- 1 were determined by its remaining procoagulant activity.N-treminal sequence was determined by the method of automated Edman degradation.[ Results ]F V e-1 was achieved by chromatography with a molecular weight of 13,808 and an isoelectric point of 4.6. The hemostatic activity of 0.5 mg Fve-1 was equal to that of 1.5625 u thrombin or that of 54.93 ng RVV X. F V e-1 primarily activated F X, but did not affect on prothrombin and fibrinogen. The suitable pH and temperature range of F V e-1 was 6.5-7.5 and 25-60 ℃,respectively.The activity of F V e-1 was enhanced by Ca2+ and inhibited by EDTA and DTT.The N-terminal sequence of F V e-1 was NH2-N-L-Y-Q-F-G-E-M-I-N.[Conclusion] F V e-1 is a factor X-activating enzyme,which could activate FX to FX a,but have minimal effect on prothrombin and fibrinogen.