Low molecular weight protamine: A potential nontoxic heparin antagonist
Low molecular weight protamine: A potential nontoxic heparin antagonist
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DOI：
10.1016/s0049-3848(98)00201-1
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发表时间：
1999-04-01
影响因子：
7.5
通讯作者：
Yang, VC
中科院分区：
文献类型：
--
作者：
Byun, Y;Singh, VK;Yang, VC
硫酸鱼精蛋白是肝素的普遍临床拮抗剂，在心血管手术后常规使用以中和肝素的抗凝功能，然而，其临床使用与不良反应相关，包括特异质致死性反应。肝素中和和鱼精蛋白毒性的机制的检查表明，肝素抗凝的逆转可能只需要一个小的鱼精蛋白的精氨酸丰富的片段静电解离抗凝血酶III从其结合到一个特定的五糖序列在肝素。文献综述表明，来自其亲本蛋白的短链肽片段通常伴随着显著降低的抗原性和免疫原性，这是鱼精蛋白通过免疫球蛋白介导的途径诱导危及生命的毒性作用的两个主要促成因素。基于这些观察结果，我们提出了我们的一般假设：如果链缩短的低分子量鱼精蛋白片段含有肝素中和结构域可以直接来自天然鱼精蛋白，它可能是一个有效的和无毒的肝素拮抗剂。在这篇文章中，我们提出了我们的实验结果来支持上述假设。用嗜热菌蛋白酶酶解天然鱼精蛋白，成功制备了平均分子量约为1.1kDa的含完整精氨酸序列的LMWP片段。体外研究表明，这种LMWP片段可完全中和肝素的抗凝作用，抗Xa显色试验和aPTT凝血时间试验结果表明，这种LMWP片段可完全中和肝素的抗凝作用。我们的体内结果表明，虽然鱼精蛋白给药小鼠导致抗鱼精蛋白抗体的明显生产，注射LMWP没有引起任何可检测的免疫原性反应。此外，LMWP片段显示出显著降低的抗原性，或者换句话说，对通过施用鱼精蛋白产生的小鼠抗鱼精蛋白抗体的交叉反应性，（C）1999 Elsevier Science Ltd.保留所有权利。
Protamine sulfate is the universal clinical antagonist to heparin and is used routinely after cardiovascular surgery to neutralize the anticoagulant function of heparin, Its clinical use, however, is associated with adverse effects including idiosyncratic fatal reactions. An examination of the mechanism of heparin neutralization and protamine toxicity suggests that the reversal of heparin anticoagulation may only require a small arginine-rich fragment of protamine to electrostatically dissociate antithrombin III from its binding to a specific pentasaccharide sequence in heparin. A review of literature indicates that chain-shortened peptide fragments derived from their parent proteins are normally accompanied with significantly reduced antigenicity and immunogenicity, which are two primary contributing factors to protamine-induced life-threatening toxic effects via an immunoglobulin-mediated pathway. Based on these observations, we propose our general hypothesis: if a chain-shortened low molecular weight protamine fragment containing the heparin-neutralizing domain could be derived directly from a native protamine, it could be a potent and nontoxic heparin antagonist. In this article, we present our experimental results to support the above hypothesis. LMWP fragments containing an intact arginine sequence and an average molecular weigh of approximately 1.1 kDa were prepared successfully by enzymatic digestion of native protamine with thermolysin, In vitro studies demonstrated that such LMWP fragments completely neutralized the anticoagulant functions of heparin, based on the anti-Xa chromogenic assay and aPTT clotting time assay. Our in vivo results indicated that while administration of protamine to mice led to obvious production of antiprotamine antibodies, injection of LMWP did not elicit any detectable immunogenic responses. In addition, the LMWP fragments showed a significantly reduced antigenicity or, in other words, cross-reactivity towards the mice antiprotamine antibodies produced by the administration of protamine, (C) 1999 Elsevier Science Ltd. All rights reserved.