SEPARATION AND CHARACTERIZATION OF ALTERED HEME PRODUCTS

血红蛋白血液代用品毒性的一种潜在机制 涉及血红蛋白与氧代谢物的反应， 缺血组织的再灌注。 这可能会导致有害的 氧化损伤的血红蛋白释放血红素的途径， 其次是有毒的铁。 我们测试了一个数字的易感性 化学修饰的血红蛋白对氢引起的氧化损伤的影响 过氧化氢（H2 O2）。 用低水平H2 O2处理血红蛋白 产生可溶性蛋白结合血红素产物， 使用HPLC分离。 人血红蛋白在α亚单位处交联 显示出比其他形式典型的氧化改性倾向 血红蛋白的变化血红素衍生的加合物从反应 H2 O2与血红蛋白的反应显示， NADPH-心肌黄酶高铁血红蛋白还原酶系统。 了类似的方法 目前正在评估其他基于血红蛋白的 红细胞替代氧化损伤，以确定 血红素和蛋白质改变的分子基础。 我们计划研究一个完整的 一系列以血红蛋白为基础的血液替代品， 肌红蛋白表现出不同的倾向， 修改. 血红蛋白氧化损伤的可能性 解决方案打开了一个关键的研究领域， 在任何当前一代血红蛋白产品之前理解 将成为成功的再灌注剂。

One potential mechanism of toxicity of hemoglobin-based blood substitutes involves the reaction of hemoglobin with oxygen metabolites formed upon reperfusion of ischemic tissues. This could lead to a deleterious pathway in which oxidatively damaged hemoglobin releases its heme and subsequently, its toxic iron. We tested the susceptibility of a number of chemically modified hemoglobins to oxidative damage caused by hydrogen peroxide (H2O2). Treatment of hemoglobins with low levels of H2O2 produced soluble protein-bound heme products that were subsequently isolated using HPLC. Human hemoglobin cross-linked at the alpha subunits showed a typical propensity to oxidative modification than other forms of hemoglobin modifications. The heme derived adducts from the reaction of H2O2 with hemoglobins showed little or no oxidase activity in the NADPH-diaphorase methemoglobin reductase system. A similar approach is currently underway to assess the susceptibility of other hemoglobin-based red cell substitutes to oxidative damage in order to determine the molecular basis of heme and protein alterations. We plan to study a full battery of Hb-based blood substitutes as well as genetically altered myoglobins that exhibit diverse tendancies to undergo oxidative modifications. The potential for oxidative damage by hemoglobin solutions opens a critical field of study that will have to be well understood before any of the present generation of hemoglobin products will be successful as a reperfusion agent.