蕲蛇酶与降纤酶的生物活性比较

目的比较蕲蛇酶和降纤酶在试管内的酶活力及在兔体血液凝固系统的生物活性。方法分别体外测定蕲蛇酶和降纤酶的相对分子质量(Mr)、蛋白质含量、精氨酸酯酶活力和凝血酶活力等。分别给家兔静脉注射蕲蛇酶0.75U/kg和降纤酶5U/kg,连续3d,比较给药前后纤维蛋白原含量、凝血酶时间、凝血酶原时间、部分凝血酶活酶时间、血小板数目、血小板聚集率、血栓长度及血栓重量的变化。结果蕲蛇酶Mr比较小(27000),且由2个Mr为15500的亚基构成,降纤酶Mr较大(40900),为单链蛋白质。0.75U蕲蛇酶和0.21U凝血酶相当;5U降纤酶约相当于1.4U凝血酶.蕲蛇酶的精氨酸酯酶活力为(973±14)μmolTAME/(mg.min),降纤酶的精氨酸酯酶活力为(1140±18)μmolTAME/(mg.min)。家兔实验,两者均能减少血栓形成及降低纤维蛋白原含量,但蕲蛇酶的药效比降纤酶强,其余指标无明显差异。结论蕲蛇酶与降纤酶不同,蕲蛇酶在生物体内(家兔)表现的药效比降纤酶强。

The comparison between the biological activities of acutobin and defibrase

PurposeTo compare the thrombin-like enzyme activity in vitro and the biological activities on the blood coagulatory system of rabbit of the antithrombotics acutobin and defibrase prepared from snake venom.MethodsThe molecular weight and the enzyme activity of these two agents were determined in vitro and comparied with thrombin. Acutobin (0.75 U/kg) and defibrase (5 U/kg)were administered intravenously into rabbits for 3 days respectively. The fibrinogen level,thrombin time, prothrombin time, partial thrombin time of blood plasma and the aggregation rate of platelets were determined before and after of the two agents were compared.ResultsThe molecular weight of acutobin was 27 000 in SDS-PAGE and 15 500 in reduced SDS-PAGE, Defibrase was 40 900 in SDS-PAGE and reduced SDS-PAGE. In vitro test: the arginine esterase activity of acutobin was (913±14) μmolTAME/(mg·min), defibrase was(1 114±18) μmolTAME/(mg·min). The coagulation activity of 0.75 U acutobin approximated to 0.21 U of thrombin, and 5 U of defibrase approximated to1.4 U of thrombin. In the coagulatory system of rabbits, the antithrombotic and defibrinogen action of the acutobin was more effective than Defibras.ConclusionAcutobin was different from defibrase in smaller molecular weight and stronger thrombin-like enzyme effect and antithrombotic activity and weaker argine esterase activity.JP]