SPECIFICITY OF ENZYMATIC PROTEIN CLEAVAGE IN GLYCEROL VS WATER

肝素是一种多阴离子糖胺聚糖，仍然是最常见的 急性冠脉综合征和急性冠脉综合征患者使用抗凝剂 正在接受心血管手术的患者。虽然这一影响 肝素对凝血系统的影响已经被很好地记录下来了，突然 停止肝素治疗可导致血栓复发 和急性胰腺炎。此外，临床上无法解释的和 接受手术的患者会发生灾难性的血栓并发症 心血管手术，尽管有足够的抗凝。内皮细胞 一氧化氮(NO)是一种重要的内源性抑制因子。 血小板介导的血栓形成；然而，生化研究检查 肝素对内皮细胞产生NO的影响迄今未见报道 一直都很缺乏。在试图解决肝素对 内皮细胞产生NO，融合的牛主动脉内皮细胞 微载体小球上的细胞(BAEC)与培养液孵育 含有新生小牛血清和L精氨酸，在或 没有肝素。结果表明，BAEC与 肝素抑制血小板聚集的能力弱于对照组 细胞，这种作用与NO的减少有关 用光解-化学发光法测定BAEC的产量。一个 BAEC暴露于ABA后，NO产量也出现了下降 等摩尔浓度的硫酸葡聚糖，表明 肝素治疗后NO的下降次于其阴性 充电，而不是特定的糖序列。这些数据表明 肝素，在急性心血管疾病中达到的浓度 设定，通过降低内皮细胞NO增加血小板聚集 制作。这些观察结果提出了一种机制，通过这种机制 部分解释肝素的血栓前作用。产品 反应的性质和机理正在进行质量研究 光谱分析。结果表明，接触NO会导致 特定硫酸盐化残留物的结构修饰。结构性的 需求和修改正在用模型进行探讨 化合物和稳定同位素标记。

Heparin a polyanionic glycosaminoglycan, remains the most commonly used anticoagulant in patients with acute coronary syndromes and in patients undergoing cardiovascular surgery. While the effects of heparin on the coagulation system have been well documented, abrupt cessation of heparin therapy can lead to a recrudescence of thrombosis and acute ischernia. In addition, clinically unexplained and catastrophic thrombotic complications occur in patients undergoing cardiovascular surgery despite adequate anticoagulation. Endothelial nitric oxide (NO) is an important endogenous inhibitor of platelet-mediated thrombosis; yet, biochemical studies examining the effect of heparin on NO production by the endothelium have heretofore been lacking. In an attempt to address heparin's effect on endothelial cell production of NO, confluent bovine aortic endothelial cells (BAEC) on microcarrier beads were incubated with media containing newborn calf serum and L-arginine, in the presence or absence of heparin. Results indicate that BAEC incubated for with heparin were less able to inhibit platelet aggregation than control cells, and that this effect correlated with a decrease in NO production by BAEC as determined by photolysis-chemiluminescence. A decrease in NO production also occurred after BAEC were exposed to an equimolar concentration of dextran sulfate, suggesting that the decrease in NO after heparin treatment is secondary to its negative charge rather than to a specific saccharide sequence. These data show that heparin, at concentrations achieved in the acute cardiovascular setting, increases platelet aggregation by decreasing endothelial NO production. These observations suggest a mechanism by which to explain, in part, the prothrombotic effects of heparin. The products of the reaction and the mechanism are being investigated by mass spectrometry. Results indicate that the exposure to NO leads to a structural modification of specific sulfated residues. The structural requirements and the modification are being probed with model compounds and stable isotope labeling.