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一、概述抗凝血酶Ⅲ(ATⅢ)是血浆中一种α_2-糖蛋白,含糖约15%。主要由肝脏合成,静脉内皮细胞亦可能参与合成.ATⅢ分子量约58000,平均血浆浓度报道不一,约15—30mg/dl。ATⅢ为天然抗凝物质中最重要的物质,已知ATⅢ通过分子中精氨酸活性中心与凝血酶分子中的丝氨酸活性中心以1:1比例结合成不具有凝血活性的复合物,而使后者失活。肝素能与ATⅢ分子上赖氨酸残基结合,从而导致ATⅢ活性中心暴露,使ATⅢ更易与凝血酶结合,故肝素能增强ATⅢ的抗凝活性。此外,ATⅢ还能使凝血因子Ⅻa,Ⅺa,Ⅹa,Ⅸa,纤溶酶及血管舒缓素等失活。ATⅢ抗凝活性占血浆总抗凝活性的75%,故当ATⅢ活性水平降低,血浆抗凝活性下降时,易发生血栓栓塞。
First, an overview of antithrombin Ⅲ (AT Ⅲ) is a plasma α 2-glycoprotein, about 15% sugar. Mainly by the liver synthesis, vein endothelial cells may also be involved in the synthesis.ATⅢ molecular weight of about 58000, the average plasma concentration reported about 15-30mg / dl. AT Ⅲ is the most important substance in natural anticoagulant substances. It is known that AT Ⅲ binds to the non-coagulant complex in a ratio of 1: 1 through the arginine active site in the molecule and the serine active site in the thrombin molecule, Inactivation. Heparin binds to the lysine residues on the ATⅢ molecule, resulting in the exposure of the AT Ⅲ active center and making ATⅢ more easily bound to thrombin. Therefore, heparin can enhance the anticoagulant activity of AT Ⅲ. In addition, AT Ⅲ can make coagulation factors Ⅻ a, Ⅺ a, Ⅹ a, Ⅸ a, plasmin and vasomotor inactivation. AT Ⅲ anticoagulant activity of total anticoagulant activity of plasma accounted for 75% of the total, so when AT Ⅲ activity decreased, anticoagulant activity decreased, prone to thromboembolism.