Machovich R, Blaskó G, Pálos L A
Biochim Biophys Acta. 1975 Jan 30;379(1):193-200. doi: 10.1016/0005-2795(75)90022-7.
Thrombin partially purified from bovine plasma can be inactivated at 60 degress C. In the presence of 10 units of heparin the extent of inactivation decreases. When thrombin and heparin are mixed and incubated for 5 min at 0 degrees C before gel filtration on Sephadex G-200, thrombin with heparin is eluted prior to either thrombin or heparin laone. These data suggest a complex formation between thrombin and heparin. Immobilized heparin binds thrombin. The enzyme can be eluted with 0.05 M Tris-HCl buffer, pH 7.3, containing an ion mixture of Na+, K+ and Ca2+ at 73, 3 and 11 mM, respectively, at 0 degrees C and with 0.05 M Tris-HCl buffer, pH 7.3, containing 0.5 M NaCl at 20 degrees C. During the same chromatographic procedure, antithrombin-III (heparin cofactor) partially purified from human plasma is eluted with 0.05 M Tris-HCl buffer, pH 7.3, at 0 degrees C as well as 20 degrees C. Although, as described in the literature, heparin binds to antithrombin, our findings suggest another possibility, i.e. that the binding of heparin to thrombin induces a conformational change in the enzyme facilitating a complex formation between thrombin and antithrombin-III.
从牛血浆中部分纯化得到的凝血酶在60摄氏度时会失活。在存在10单位肝素的情况下，失活程度会降低。当凝血酶和肝素混合并在0摄氏度下孵育5分钟后，再在葡聚糖凝胶G - 200上进行凝胶过滤时，凝血酶与肝素的复合物会先于单独的凝血酶或肝素被洗脱出来。这些数据表明凝血酶和肝素之间形成了复合物。固定化肝素能结合凝血酶。该酶可以在0摄氏度下用含有分别为73、3和11 mM的Na +、K +和Ca2 +离子混合物的0.05 M Tris - HCl缓冲液（pH 7.3）洗脱，也可以在20摄氏度下用含有0.5 M NaCl的0.05 M Tris - HCl缓冲液（pH 7.3）洗脱。在相同的色谱过程中，从人血浆中部分纯化得到的抗凝血酶III（肝素辅因子）在0摄氏度和20摄氏度下都能用0.05 M Tris - HCl缓冲液（pH 7.3）洗脱。虽然如文献所述，肝素会与抗凝血酶结合，但我们的发现提示了另一种可能性。即肝素与凝血酶的结合会诱导该酶发生构象变化，从而促进凝血酶与抗凝血酶III之间形成复合物。
