Interaction of antithrombin III with bovine aortic segments. Role of heparin in binding and enhanced anticoagulant activity.
Interaction of antithrombin III with bovine aortic segments. Role of heparin in binding and enhanced anticoagulant activity.
复制标题
抗凝血酶 III 与牛主动脉段的相互作用。
DOI：
10.1172/jci111685
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Stern,K
中科院分区：
文献类型：
--
作者：
Stern,D;Nawroth,P;Marcum,J;Handley,D;Kisiel,W;Rosenberg,R;Stern,K
研究了牛抗凝血酶III（AT III）与具有连续内皮层的牛主动脉节段的管腔表面的相互作用。孵育125 I-AT III与血管节段，先前洗的内源性AT III，表现出特定的，时间依赖性结合的蛋白酶抑制剂的内皮细胞。在添加的AT III浓度为14 nM时观察到半最大结合。125 I-AT III与血管壁的结合是可逆的（4 min内解离50%），加入肝素或Xa因子可加速125 I-AT III从血管段的位移。在Xa因子存在下，125 I-AT III从血管段解离与Xa因子-125 I-AT III复合物的形成一致。在血管节段存在的情况下，AT III可促进因子IXa和因子Xa的灭活。用高度纯化的黄杆菌肝素酶预处理血管段，排除了AT III抗凝活性的血管依赖性增强以及125 I-AT III与血管内皮的特异性结合。与此相反，预处理的血管节段与chrondroitinases（ABC或AC）没有检测到的影响125 I-AT III结合或AT III抗凝活性。AT III结合血管节段竞争性抑制血小板因子4的浓度增加。结合的蛋白酶抑制剂的血管节段被抑制AT III赖氨酰或色氨酸残基的化学修饰。这些AT III衍生物保留了渐进的抑制活性。这些数据表明，肝素样分子存在于主动脉血管壁上，介导AT III与血管表面的结合，并增强AT III在这些部位的抗凝活性。图片
Bovine antithrombin III (AT III) interaction with the luminal surface of bovine aortic segments with a continuous layer of endothelium was examined. Incubation of 125I-AT III with vessel segments, previously washed free of endogenous AT III, demonstrated specific, time-dependent binding to the protease inhibitor to the endothelium. Half-maximal binding was observed at an added AT III concentration of 14 nM. Binding of 125I-AT III to the vessel wall was reversible (50% dissociated in 4 min), and addition of either heparin or Factor Xa accelerated displacement of 125I-AT III from the vessel segment. Dissociation of 125I-AT III from the vessel segment in the presence of factor Xa coincided with the formation of a Factor Xa-125I-AT III complex. Inactivation of Factor IXa and Factor Xa by AT III was facilitated in the presence of vessel segments. Pretreatment of vessel segments with highly purified Flavobacterium heparinase precluded the vessel-dependent augmentation of AT III anticoagulant activity as well as specific binding of 125I-AT III to the vessel endothelium. In contrast, pretreatment of the vessel segments with chrondroitinases (ABC or AC) had no detectable effect on 125I-AT III binding or on AT III anticoagulant activity. AT III binding to vessel segments was competitively inhibited by increasing concentration of platelet factor 4. Binding of the protease inhibitor to vessel segments was inhibited by chemical modification of AT III lysyl or tryptophan residues. These AT III derivatives retained progressive inhibitory activity. These data suggest that heparin-like molecules are present on the aortic vessel wall and mediate binding of AT III to the vessel surface, as well as enhancing the anticoagulant activity of AT III at these sites.Images