Datta G, Dong A, Witt J, Tu A T
Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins 80523.
Arch Biochem Biophys. 1995 Mar 10;317(2):365-73. doi: 10.1006/abbi.1995.1176.
Snake venoms, especially from the Crotalidae family, contain a variety of enzymes that prevent blood coagulation by virtue of their fibrinolytic enzymes. Nineteen snake venoms were screened for fibrinolytic activity and the highest activity was found in the venom of Crotalus basiliscus basiliscus venom. The active principle, basilase, was isolated, purified, and found to have fibrinolytic and fibrinogenolytic activity. It had a molecular weight of 22,000 and 1 mol of zinc per mole of protein associated with it. The proteolytic activity of the enzyme against dimethyl casein was inhibited by ethylenediaminetetraacetic acid and alpha 2-macroglobulin. It did not inactivate alpha 2-macroglobulin. Basilase did not have any of the following activities: thrombin-like, factor X-like, protein C activating, or urokinase-like. It caused neither hemorrhage nor platelet aggregation. In spite of its proteolytic activity, basilase did not hydrolyze the membranes of platelets. Basilase had 24% alpha-helix, 31% beta-sheet, 25% turns, and 20% unordered structure, as determined by Fourier Transform Infrared spectroscopy. Basilase is an enzyme that hydrolyzes fibrin directly without activation of plasminogen.
蛇毒，尤其是蝰蛇科的蛇毒，含有多种酶，这些酶凭借其纤维蛋白溶解酶来阻止血液凝固。对19种蛇毒进行了纤维蛋白溶解活性筛选，发现墨西哥跳蝮蛇毒的活性最高。分离并纯化了其活性成分巴西溶纤酶，发现它具有纤维蛋白溶解和纤维蛋白原溶解活性。它的分子量为22000，每摩尔蛋白质含有1摩尔锌。该酶对二甲基酪蛋白的蛋白水解活性受到乙二胺四乙酸和α2-巨球蛋白的抑制。它不会使α2-巨球蛋白失活。巴西溶纤酶不具有以下任何活性：类凝血酶、类X因子、蛋白C激活或类尿激酶活性。它既不会导致出血也不会引起血小板聚集。尽管具有蛋白水解活性，但巴西溶纤酶不会水解血小板膜。通过傅里叶变换红外光谱测定，巴西溶纤酶具有24%的α-螺旋、31%的β-折叠、25%的转角和20%的无规结构。巴西溶纤酶是一种直接水解纤维蛋白而不激活纤溶酶原的酶。
