CHARACTERIZATION OF HEMATIN DERIVED ANTICOAGULANT

本建议书所述的项目旨在确定 血红素衍生物的生物化学、生物学和药理学意义 抗凝剂（HDA）。 HDA延长体外凝血时间 和体内。 HDA是一种衍生物或降解产物， 当血红素被允许在溶液中静置时，或者当它被注入 大鼠 HDA将在体外和体内进行纯化和鉴定 来源色谱和光谱技术。 这将考验 假设HDA是血红素（血红素）的单一衍生物， 能够与凝血蛋白相互作用， 功能效应。 HDA与特异性的 蛋白质纤维蛋白原、凝血酶和因子VIII：C将被定义为 测定结合亲和力和对酶功能的影响， 天然和合成底物。 紫外-可见分光光度计的具体技术 光谱学、平衡透析和铁结合拮抗 化合物将检验铁或微量金属参与的假设 HDA与凝血蛋白的相互作用。 生产和 HDA在体内的机制将用分离的肝血红素来定义 代谢系统和整个动物。 这将检验假设， HDA是血红素的代谢产物，其机制与 在试管中看到的。 具体技术涉及放射性同位素和 药理学探针 最后，HDA的药理学潜力将是 通过使用放射性标记的药物代谢动力学和有效性研究确定 HDA和各种给药途径。 完成这些研究将 定义HDA的生物化学、生理学和药理学意义。

The project described in this proposal is designed to define the biochemical, biologic and pharmacologic significance of hematin-derived anticoagulant (HDA). HDA produces prolongation of clotting times in vitro and in vivo. HDA is a derivative or degradation product which is produced when hematin is allowed to stand in solution or when it is infused into rats. HDA will be purified and identified from in vitro and in vivo sources by chromatographic and spectroscopic techniques. This will test the hypothesis that HDA is a single derivative of hematin (heme) which is capable of interacting with coagulation proteins to produce profound functional effects. The mechanism of interaction of HDA with the specific proteins fibrinogen, thrombin and factor VIII:C will be defined by determining binding affinities and effects on enzymatic function with natural and synthetic substrates. The specific techniques of UV-Vis spectroscopy, equilibrium dialysis and antagonism with iron binding compounds will test the hypothesis that iron or a trace metal is involved in the interaction of HDA with clotting proteins. The production and mechanism of HDA in vivo will be defined with isolated hepatic heme metabolic systems and whole animals. This will test the hypothesis that HDA is a metabolic product of heme and that the mechanism is identical to that seen in vitro. Specific techniques involve radioisotope and pharmacologic probes. Finally, the pharmacologic potential of HDA will be determined by pharmacokinetic and efficacy studies utilizing radiolabelled HDA and various routes of administration. Completion of these studies will define the biochemical, physiologic and pharmacologic significance of HDA.