MOLECULAR MECHANISMS OF BLOOD COAGULATION ACTIVATION

这个项目的长期目标是一个完整的 在分子水平上理解接触激活 血液凝固及其影响因素。这涉及到 导出所有结合作用的参数，包括 高分子量激肽原等蛋白质和表面； 凝血因子XII和因子自身激活的机制 高分子量激肽原在其中的作用； 表面相互作用活化的动力学参数 凝血因子XII和前激肽释放酶以及凝血因子XI的激活。 将特别注意二价阳离子作为 表面催化反应中的辅因子。此外，监管 缓蚀剂对接触的活化作用，以及动力学参数 在表面存在的情况下产生缓激肽和纤溶酶， 将会被评估。这些研究将使用荧光 偏振、荧光共振能量转移、酶 动力学和快速反应动力学技术。量化数据 将获得化学计量比、亲和力和速率 所涉及的各种相互作用，使用纯化的系统以及 正常的和缺乏的血浆。预计这一项目 将会加深对分子的理解 接触激活机制及其影响因素， 以及依赖于XII的每个因子的相对重要性 路径。阐明这些机制可以提供基本的 有关血栓栓塞性疾病的原因以及 受接触蛋白影响的其他病理状态 激活系统。

The long range objective of this project is a complete understanding, at the molecular level, of contact activation of blood coagulation and the factors affecting it. This involves educidation of the parameters of all binding interactions involving high molecular weight kininogen and other proteins and surfaces; the mechanism of autoactivation of factor XII and factors affecting it; the role of high molecular weight kininogen and surfaces on the kinetic parameters for reciprocal activation of factor XII and prekallikrein as well as the activation of factor XI. Particular attention will be paid to the role of divalent cations as cofactors in surface-catalyzed reactions. In addition, regulation of contact activation by inhibitors, and the kinetic parameters for generation of bradykinin and plasmin in the presence of surfaces, will be evaluated. These studies will use fluorescence polarization, fluorescence resonance energy transfer, enzyme kinetics and rapid reaction kinetic techniques. Quantitative data will be obtained for the stoichiometries, affinities and rates of the various interactions involved, using purified systems as well as normal and deficient plasmas. It is anticipated that this project will result in enhanced understanding of the molecular mechanisms of contact activation and the factors which affect it, as well as the relative importance of each factor XII-dependent pathway. Elucidation of these mechanisms can provide basic information on the cause of thromboembolytic disorders as well as other pathologic states affected by the proteins of the contact activation system.