KINETICS OF NITRIC OXIDE BINDING TO HEMOPROTEINS

对血红蛋白输注的高血压反应已经被证实是 归因于血红蛋白和内皮衍生的 一氧化氮（NO）。 我们探讨了NO与细胞内NO的相互作用， 三价铁形成了一些化学修饰。 最初的差异 NO与几种化学修饰血红蛋白的铁结合 以及在缓慢过程中的差异，其中NO 驱动血红素还原。 由于NO将氧合血红蛋白氧化成三价铁， 血红蛋白（metHb）非常迅速地在体内，我们假设， NO和高铁血红蛋白之间的氧化还原循环可能是部分原因 NO作为生物换能器的耗尽，导致改变 不同血红蛋白对血管张力有不同影响 准备工作 在缺血条件下，超氧化物的存在可以 潜在地减弱NO的血管舒张作用，通过与 NO导致另一种强氧化剂的形成， 过氧亚硝酸根（ONOO-）。 天然和化学改性的反应 血红蛋白导致血红素铁快速氧化成三价铁 和可能的其它氧化产物。 从快速获得的时间课程 动力学实验表明亚铁氧化态的双相损失 把过氧亚硝酸盐和血红蛋白混在一起 使用比色法和 荧光免疫检测技术，我们能够表明， 酪氨酸硝化过氧化氢可以发生与天然和 修饰血红蛋白 对输注的全身和肾脏反应 未修饰的、交联的和聚合的交联血红蛋白被 在麻醉的老鼠身上进行了研究。 未修饰的血红蛋白产生显著 平均动脉血压（MAP）在整个60 分钟输液。另一方面，交联血红蛋白产生的 MAP显著且持续增加超过120分钟。 只有温和的 在大鼠中观察到在30分钟输注 聚合蛋白质 肾功能不全的症状有哪些？ 通过肾小球滤过率（GRF）测定的蛋白质含量在 未修饰血红蛋白>聚合血红蛋白>交联血红蛋白。

The hypertensive response to the infusion of hemoglobin has been attributed to the reaction between hemoglobin and the endothelial derived nitric oxide (NO). We explored the interactions of between NO and the ferric form a number of chemically modified. Differences in the initial NO binding to the ferric forms of several chemically modified hemoglobins were observed as well as differences in the slow process in which NO drives the heme reduction. Since NO oxidizes oxyhemoglobin to the ferric hemoglobin (metHb) extremely rapidly in vivo, we hypothesized that a redox cycle between NO and the metHb could be partially responsible for the depletion of NO as a biological transducer, leading to altered vascular tone with variable effects observed for different hemoglobin preparations. The presence of superoxide under ischemic conditions can potentially abate the vasorelaxing effects of NO, by direct reaction with NO leading to the formation of yet another powerful oxidant, peroxynitrite (ONOO-). Reactions of native and chemically modified hemoglobins leads to rapid oxidation of the heme iron to the ferric form and possibly other oxidation products. Time courses obtained from rapid kinetic experiments showed a biphasic loss of the ferrous oxidation state on mixing peroxinitrite with these hemoglobins. Using colorimetric and chemiluminescent immunodetection techniques we were able to show that tyrosine nitration by peroxynitite can occur with both native and modified hemoglobins. Systemic and renal responses to the infusion of unmodified, cross-linked and polymerized cross-linked hemoglobins were studied in anesthetized rats. Unmodified hemoglobin produced significant increase in the mean arterial blood pressure (MAP) throughout the 60 minute infusion. Cross-linked hemoglobin, on other hand, produced a more marked and prolonged increase in MAP over 120 minutes. Only a moderate increase in MAP were observed in rats after 30 minutes infusion with the polymerized protein. The extent of renal insufficiency produced by these proteins, as determined by the Glomarular Filtration rate (GRF) were in the following order, unmodified Hb > polymerized Hb > cross-linked Hb.