从美洲钝眼蜱（Amblyomma americanum (L.)）唾液腺中分离并鉴定凝血酶特异性抑制剂美洲毒素。
Isolation and characterization of americanin, a specific inhibitor of thrombin, from the salivary glands of the lone star tick Amblyomma americanum (L.).
作者信息
Zhu K, Bowman A S, Brigham D L, Essenberg R C, Dillwith J W, Sauer J R
机构信息
Department of Entomology, Oklahoma State University, Stillwater 74078, USA.
出版信息
Exp Parasitol. 1997 Sep;87(1):30-8. doi: 10.1006/expr.1997.4175.
A thrombin (EC 3.4.21.5) inhibitor (americanin) was isolated from the salivary glands of the lone star tick Amblyomma americanum (L.) using reversed-phase chromatography and anion-exchange chromatography. Americanin did not inhibit any other protease tested, including factor Xa, plasmin, trypsin, chymotrypsin, elastase, papain, pepsin, and carboxypeptidase. The inhibition of thrombin by americanin decreased dramatically with dilution of the reaction mixture including thrombin, its substrate, and americanin. When thrombin assays were performed in the presence of americanin, the reaction curve showed a time-dependent inhibition. Significant inhibition was observed when americanin concentration was approximately equal to that of thrombin, with a Ki of 0.073 nM. The results suggest that americanin is a specific, reversible, competitive, slow, tight-binding inhibitor of thrombin.
利用反相色谱法和阴离子交换色谱法，从美洲钝眼蜱（Amblyomma americanum (L.)）的唾液腺中分离出一种凝血酶（EC 3.4.21.5）抑制剂（美洲蛋白）。美洲蛋白对所测试的其他任何蛋白酶均无抑制作用，这些蛋白酶包括因子Xa、纤溶酶、胰蛋白酶、糜蛋白酶、弹性蛋白酶、木瓜蛋白酶、胃蛋白酶和羧肽酶。随着包含凝血酶、其底物和美洲蛋白的反应混合物的稀释，美洲蛋白对凝血酶的抑制作用显著降低。当在美洲蛋白存在的情况下进行凝血酶测定时，反应曲线呈现出时间依赖性抑制。当美洲蛋白浓度约等于凝血酶浓度时，观察到显著抑制作用，其抑制常数（Ki）为0.073 nM。结果表明，美洲蛋白是一种特异性、可逆、竞争性、缓慢、紧密结合的凝血酶抑制剂。
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