HEPARIN STRUCTURE IN PREPARING NEW ANTICOAGULANTS

制备新型抗凝剂的肝素结构

• 批准号: 3340863
• 负责人: ROBERT J LINHARDT
• 金额: $ 8.18万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-06-01 至 1990-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3340863
• 关键词: X ray crystallography; anticoagulants; binding proteins; blood /lymphatic pharmacology; carbohydrate biosynthesis; chemical structure function; drug adverse effect; drug design /synthesis /production; drug metabolism; drug screening /evaluation; heparin; magnetic resonance imaging; pharmacokinetics; protease inhibitor; proteoglycan; spectrometry

Heparin, a polydisperse, highly sulfated polysaccharide, is the most commonly used clinical anticoagulant. Despite the yearly use of over 50 million doses in the U.S. alone, heparin's exact chemical structure and the precise nature of its anticoagulant and antithrombotic activities remains unclear. Heparin anticoagulation results in frequent (8-33%) hemorrhagic complications, making it "the drug responsible for the most deaths in otherwise healthy patients" (Boston Collaborative Drug Surveillance Program). Recent clinical studies on low molecular weight (LMW) heparins (and heparinoids) demonstrate the dissociation of heparin's antithrombotic activities from its hemorrhagic side-effects. Despite this success, LMW heparins are still polydisperse, poorly characterized mixtures. The long term objective of this research is the preparation of pure structurally characterized LMW heparins with: high specificity; improved pharmacokinetics and bioavailability; and high antithrombotic activity with low hemorrhagic side-effects. The specific aims of this proposal are the following: 1. To screen a library of pure heparin fragments for their ability to bind to serine proteases serine protease inhibitors and for their ability to potentiate the inhibition of these proteases; 2. To assemble a manageable number of these fragments having both specific and non-specific binding affinities and (or) activities and to determine their chemical structure; 3. To test the activity of these pure heparin fragments using a variety of in vitro assays and to submit these to Dr. Fareed for evaluation as antithrombotic agents in vivo; 4. To examine both proteoglycan and raw heparin for the presence of these active sequences in order to relate these studies to heparin's "true biological functions." Heparin will be enzymatically depolymerized, fractionated by size and charge to obtain pure oligosaccharides and their activity (in vitro) and binding affinity to purified coagulation proteins will be measured. The structure of biologically interesting oligosaccharides will be determined by an integrated approach involving chemical, enzymatic and spectroscopic methods. SAR studies will use molecular graphics to compare the activities of a large number of structurally defined oligosaccharides. Direct comparison of the results obtained on clinically used commercial heparins with those obtained on proteoglycan heparins prepared from tissue will result in a better understanding of heparin's "true biological functions."

肝素是多脱糖，高度硫化的多糖，是 最常用的临床抗凝剂。 尽管每年 仅在美国就使用超过5000万剂，肝素的确切剂量 化学结构及其抗凝剂的精确性和 抗血栓性活动尚不清楚。 肝素抗凝导致频繁（8-33％）出血 并发症，使其“导致最多死亡的药物 在其他健康的患者中”（波士顿协作药物 监视计划）。 低分子的最新临床研究 重量（LMW）肝素（和肝素）证明了 肝素的抗血栓性活动与其解离 出血副作用。 尽管取得了成功，LMW肝素是 仍然多分散，特征性的混合物不佳。 这项研究的长期目标是准备纯 结构表征的LMW肝素具有：高特异性； 改进的药代动力学和生物利用度；和高 抗血栓性活性低，具有低出血性副作用。 该提案的具体目的是：1。筛选 纯肝素碎片的库，以使其与 丝氨酸蛋白酶丝氨酸蛋白酶抑制剂及其能力 增强对这些蛋白酶的抑制作用； 2。组装 具有特定和 非特异性结合亲和力和（或）活动，并确定 它们的化学结构； 3。测试这些纯净的活动 肝素碎片使用各种体外测定法，并提交 这些是向Fareed博士评估的 体内4。检查蛋白聚糖和原始肝素的 这些主动序列的存在是为了关联这些研究 肝素的“真正的生物学功能”。 肝素将被酶促解聚，按大小分级 并充电以获得纯寡糖及其活性（在 体外）和与纯化的凝结蛋白的结合亲和力将是 测量。 生物学上有趣的结构 寡糖将通过综合方法确定 涉及化学，酶和光谱法。 sar 研究将使用分子图形来比较 大量结构定义的寡糖。 直接的 比较临床使用商业的结果 肝素与准备的蛋白聚糖肝素获得的肝素 从组织中可以更好地了解肝素的“真实 生物功能。”