摘要
烙铁头(T.mucrosquamatus)蛇毒纤维蛋白原溶酶TMVFg能水解三肽底物Bz-Phe-Val-Arg-PNA,但对凝血酶的良好底物Cbz-Gly-Pro-Arg-PNA却活性甚低。TMVFS显著延长血浆凝血酶时间。血浆复钙时间及纤维蛋白原溶液凝血酶时间。同时,TMVFg体外也能延长全血凝固时间,表明具有抗凝作用。纤维蛋白原-纤维蛋白转换实验表明:TMVFg水解纤维蛋白原产生的纤维蛋白原断片(FDP)除具有抗凝血酶,抑制纤维蛋白聚合活性外,还能促进纤维蛋白的聚合。 进一步用FPLC分离TMVFg水解人纤维蛋白原混合液,得两个FDP断片功能峰,FDP组分Ⅰ和FDP组分Ⅱ。其中FDP组分Ⅰ能抑制纤维蛋白凝块形成;FDP组分Ⅱ能促进纤维蛋白凝块形成,抑制TMVA(烙铁头蛇毒血小板活化素,它可不通过ADP、花生四烯酸途径而诱导血小板聚集),但对ADP诱导的家兔血小板聚集无影响。TMVFg对凝血酶水解三肽底物Cbz-Gly-Pro-Arg-PNA及凝固纤维蛋白原的活性也有一定抑制作用。 实验证明,TMVFg抗凝的主要作用机理是其水解纤维蛋白原产生的断片对纤维蛋白原凝固的抑制作用、FDP断片抗凝血酶作用及TMVFg本身对凝血酶活性的抑制所引起的,但在二者之间,前者是主要的。 从研究结果发现:TMVFg水解纤维蛋白原所产生的断片有一类能加速凝血酶凝固纤维蛋白原的过程,这就发现了FDP断片的?
The fibrinogenase of T.mucrosquamatus venom(TMVFg)could hydrolyze the tripeplide Bz-Phe-Val-Arg-PNA’ but it sbwed low enzymatic activity toward Cbz-Gly-Pro-Arg-PNA which was a good substrate of thrombin.TMVFg apparently prolonrd plasma thrombin time, plas。a re。alcification time and fibrinogn solution thrombin time. By using MonoQ ion-exchange chromatography (EPLC),fibrinogen products degraded with TMVFg were isolated·One,designated as FDPI,inhibited fibrin
clot formatic。f Another onet desig。ated as FDPI,l not only enhanced the fibrin clot but also inhibhed platelet aggregation inducedby TMVA(al platelel aggregation inducer isolated from the venom of T.m。cro。c。。a。af。。。)a。dK。is i。lllbitory effect was Jose dependent.卜DPILad。。 effecto。 pl。teLt。ggr。gation inducedby ADPorby a,achido。Ic acid(AA)· The resuhs al。o showed (ha TMVFg hadcertain inhibitory effect on thrombin activities.
关键词
烙铁头蛇
纤维蛋白原
蛇毒
凝血酶
Fibrinogen degraded products, Fibrinogen, Snake venom,Thrombin
