Fischer A M, Tapon-Bretaudiere J, Bros A, Josso F
Thromb Haemost. 1981 Feb 23;45(1):51-4.
In order to investigate the mechanism of thrombin inactivation in the presence of both antithrombin III (AT III) and alpha 2-macroglobulin (alpha 2 M), thrombin and the inhibitors have been purified from human material and thrombin inactivation studied using purified reagents either alone or added to defibrinated plasma. Comparison of clotting and amidolytic activities of residual thrombin allowed to measure the amount of thrombin bound to alpha 2 M. In a purified reagent system as well as in plasma, part of exogenous thrombin is bound to alpha 2 M. The amount of bound thrombin is related to alpha 2 M concentration. Conversely, previous plasma alpha 2 M depletion by immunoabsorption increases the consumption of heparin-cofactor activity by exogenous thrombi. Thus AT III and alpha 2 M compete for thrombin inactivation. This finding could be of practical interest in clinical situations associating high plasma alpha 2 M levels and a decrease of AT III concentrations.
为了研究在抗凝血酶III（AT III）和α2-巨球蛋白（α2M）同时存在的情况下凝血酶失活的机制，已从人源材料中纯化了凝血酶和抑制剂，并使用纯化的试剂单独或添加到去纤维蛋白血浆中研究凝血酶失活情况。通过比较残留凝血酶的凝血活性和酰胺水解活性，可以测定与α2M结合的凝血酶量。在纯化的试剂系统以及血浆中，部分外源性凝血酶会与α2M结合。结合的凝血酶量与α2M浓度有关。相反，先前通过免疫吸附使血浆α2M耗竭会增加外源性凝血酶对肝素辅因子活性的消耗。因此，AT III和α2M竞争使凝血酶失活。这一发现对于血浆α2M水平升高和AT III浓度降低相关的临床情况可能具有实际意义。
