SEPARATION AND CHARACTERIZATION OF ALTERED HEME PRODUCTS

以血红蛋白为基础的血液替代品毒性的一个潜在机制 涉及到血红蛋白与氧代谢产物的反应 缺血组织再灌流。这可能会导致有害的 氧化损伤的血红蛋白释放其血红素和 随后，其有毒的铁。我们测试了一个数字的敏感性 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(过氧化氢)。低浓度H_2O_2处理血红蛋白 生产了可溶的蛋白质结合的血红素产品，随后 用高效液相色谱分离。人血红蛋白在α亚基上交联化 表现出比其他形式更典型的氧化修饰倾向 对血红蛋白的修饰。血红素从反应中衍生出加合物。 H_2O_2与血红蛋白的结合显示很少或没有氧化酶活性 NADPH-黄递酶高铁血红蛋白还原酶系统。一种类似的方法是 目前正在评估其他基于血红蛋白的易感性 以确定红细胞替代物对氧化损伤的影响 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 一组基于Hb的血液替代品以及经过基因改造的 肌红蛋白表现出不同的氧化倾向 修改。血红蛋白造成氧化损伤的可能性 解决方案打开了一个关键的研究领域，必须做好 比当代任何一代血红蛋白产品都更早了解 作为一种再灌注剂会很成功。

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.