Department of Biochemistry & Molecular Biology, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou 510006, China.
Thromb Res. 2009 Nov;124(5):631-9. doi: 10.1016/j.thromres.2009.06.022. Epub 2009 Aug 15.
Thrombin-like enzyme (TLE) plays a significant role in vessel injury hemostasis. A novel snake venom TLE (Agacutin) was purified from Agkistrodon Acutus snake venom. Structural analysis indicated that Agacutin is a heterodimer that has a MW of 29,402 Da, a pI value of 5.39, and optimum activity at 35 degrees C and pH 7.5. The N-terminal 15 amino acid sequences of Agacutin are DSSGWSSYEGHEYYV (small subunit) and DCSSGWSSYEEHQYY (large subunit). In vitro studies indicated that the coagulation activity of Agacutin was activated by Ca(+2) or inhibited by phenylmethanesulfonyl fluoride, but not influenced by heparin or hirudin. The arginine esterase activity and fibrinogen hydrolysis result showed that Agacutin only cleaves alpha-subunit and releases fibrinopeptide A. In vivo studies indicated that Agacutin iv (0.01-0.05 U/kg) shortened 30.2-49% of the rabbit blood clotting time, or ip (0.5-2.0 U/kg) shortened 29.7-73.1% of the mouse tail bleeding time. Agacutin does not influence APTT, platelet or euglobulin clotting time, and activate Factor II or XIII. It converts fibrinogen into the soluble fibrin that accelerates hemostasis at wound.
类凝血酶（TLE）在血管损伤止血中起着重要作用。一种新型蛇毒 TLE（Agacutin）从尖吻蝮蛇蛇毒中纯化得到。结构分析表明，Agacutin 是一种异二聚体，MW 为 29402 Da，pI 值为 5.39，最适活性在 35°C 和 pH7.5。Agacutin 的 N 端 15 个氨基酸序列为 DSSGWSSYEGHEYYV（小亚基）和 DCSSGWSSYEEHQYY（大亚基）。体外研究表明，Agacutin 的凝血活性被 Ca(+2)激活或被苯甲基磺酰氟抑制，但不受肝素或水蛭素影响。精氨酸酯酶活性和纤维蛋白原水解结果表明，Agacutin 仅裂解 alpha 亚基并释放纤维蛋白肽 A。体内研究表明，Agacutin iv（0.01-0.05 U/kg）可缩短家兔凝血时间的 30.2-49%，或 ip（0.5-2.0 U/kg）可缩短小鼠尾巴出血时间的 29.7-73.1%。Agacutin 不影响 APTT、血小板或优球蛋白凝固时间，也不激活因子 II 或因子 XIII。它将纤维蛋白原转化为可溶性纤维蛋白，加速伤口止血。
