SEPARATION AND CHARACTERIZATION OF ALTERED HEME PRODUCTS

过氧化氢（HOOH）的增加被认为是在以下条件下发生的： 缺氧后用含氧培养基进行组织再灌注的结果。 我们刚 表明当修饰的血红蛋白被HOOH攻击时， 并形成潜在的有毒物质，包括铁蛋白 自由基（Fe+4）。 我们最近发布了一个机制，基于 基于时间的光谱数据的奇异最小二乘动力学分析， 充分描述了一些修饰的血红蛋白与 呼。我们已经提出，除了修饰配体相互作用外， 特定的修饰也可以影响血红蛋白的倾向， 进行氧化改性并产生铁基物质。 在HOOH存在下，铁和铁酰血红素之间的循环 可以导致明显的过氧化物酶活性， 活性也依赖于蛋白质的结构修饰。 在另一组实验中，血红蛋白A0的铁形式及其 将交联衍生物加入到脂质体的悬浮液中。 两 系统中的血红素蛋白和脂质成分经历了 化学变化 它们之间促氧化活性的差异 血红蛋白被发现是或差异群体 它们的铁基中间体或不同的二聚和血红素的转移 进入细胞膜，随后血红素降解。 由于血管 内皮细胞是第一个接触循环系统的细胞， 血红蛋白为基础的血液替代品，我们研究的影响， 不同修饰血红蛋白对牛主动脉完整性的影响 内皮细胞（BAEC）和HOOH介导的细胞毒性。 我们发现 未修饰的血红蛋白A0对过氧化物诱导的 内皮细胞坏死，可能是由于其过氧化物酶活性。 然而，分子内和分子间交联血红蛋白 保护免受过氧化物诱导的内皮细胞损伤。

Increased hydrogen peroxide (HOOH) is thought to occur under conditions of tissue reperfusion with oxygenated media after hypoxia. We were first to show that when modified hemoglobins are challenged with HOOH, damaging and potentially toxic species are formed including the ferryl protein radical (Fe+4). We have recently published a mechanism, based on singular least squares kinetic analysis of time-based spectral data, to describe fully the interactions of a number of modified hemoglobins with HOOH. We have suggested that besides modifying ligand interactions, site specific modification can also affect the tendency of hemoglobin to undergo oxidative modification and the production of the ferryl species. Cycling between the ferric and the ferryl heme in the presence of HOOH can result in apparent peroxidase activity, and that the level of activity also being dependant on structural modification of the protein. In another set of experiments the ferric forms of hemoglobin A0 and its cross-linked derivatives were added to suspensions of liposomes. Both the hemoprotein and the lipid constituents of the system underwent chemical change. Differences in the pro-oxidant activities among these hemoglobins were found to be either to the differential population of their ferryl intermediates or disparate dimerization and transfer of heme into membrane with subsequent heme degradation. Since the vascular endothelium is the first in line to exposure of circulating hemoglobin-based blood substitutes, we investigated the effects of a variety of modified hemoglobin on the integrity of bovine aorta endothelial cells (BAEC) and on the HOOH mediated cytotoxicity. We found that unmodified hemoglobin A0 to be protective against peroxide-induced endothelial cell necrosis, probably due to its peroxidase activity. Intra- and intermolecular cross-linked hemoglobin, however, did not protect against peroxide-induced endothelial cell damage.