MODIFIED HEMOGLOBINS AS A SOURCE OF ACTIVATED OXYGEN SPECIES

基于血红蛋白的氧气载体(HBOC)是用作血液的候选材料 代用品和复苏液。我们已经确定了这种化学物质 用于产生α-交联型血红蛋白的修饰 或β链改变它们产生氧或与氧相互作用的能力 激进分子。交联型血红蛋白暴露在超氧化物(O2)中 由黄嘌呤/黄嘌呤氧化酶系统产生的 羟基(.oh)和/或具有类似反应活性的其他自由基。我们的 结果表明，每种HbOCs显示出显著的差异。 在涉及生产的反应中的其他和来自未修饰的血红蛋白 这些氧自由基中。铁的相对能力 监测了参与自由基反应的HBOCs的衍生物 通过非酶NADPH氧化和苯胺羟化反应(反应 由活性氧物种调节)。再次交联型血红蛋白 在与氧物种的反应性方面表现出显著的差异 如过氧物和超氧化物。在最近的实验中，氢 过氧化氢是在连续的熔剂中产生的，以模拟细胞 条件，由葡萄糖/葡萄糖氧化酶系统决定。相对于未修改 HbAo，我们发现一些交联的血红蛋白更容易患上 氧化修饰和形成剧毒的铁基物种。 这种形式的氧化修饰可能会在生理上出现 可能导致对再灌注有重大贡献的重要事件 受伤。 为了继续下去，计划进行一些体外和体内研究。 检查血红蛋白介导的自由基的产生并确定如何 这些自由基可能加重缺血动物的“再灌注损伤” 模特。其中一些研究的结果在第四次会议上公布。 血液替代品国际研讨会，1991年，加拿大。一份手稿 对其中一些工作的描述已发表在《建筑》杂志上。生物化学。生物群落。 另一份手稿已提交《生物化学》杂志发表。生物群落。 研究结果：Comm.

Hemoglobin-based oxygen carriers (HBOCs) are candidates for use as a blood substitute and resuscitation fluid. We have established that chemical modification used to generate hemoglobins cross-linked at either the alpha or beta chains alter their ability to generate or interact with oxygen free radicals. Exposure of cross-linked hemoglobins to superoxide (O2) generated by the xanthine/xanthine oxidase system causes generation of hydroxyl radicals (.OH) and/or other radicals with similar reactivity. Our results indicate that HBOCs exhibit a significant difference from each other and from unmodified hemoglobins in reactions involving the production of these oxygen free radicals. The relative ability of the ferric derivatives of HBOCs to participate in free radical reactions was monitored by nonenzymatic NADPH oxidation and aniline hydroxylation assays (reactions mediated by reactive oxygen species). Cross-linked hemoglobins again exhibited significant differences in their reactivity with oxygen species such as peroxides and superoxides. In more recent experiments, hydrogen peroxide was produced in a continuous flux, in order to mimic the cellular conditions, by the glucose/glucose oxidase system. Relative to unmodified HbAo, we found that some cross-linked hemoglobins are more susceptible to oxidative modification and the formation of a highly toxic ferryl species. This form of oxidative modification may emerge as a physiologically important event which may lead to a significant contribution to reperfusion injury. A number of in vitro and in vivo studies are planned in order to continue to examine the hemoglobin-mediated radical generation and to determine how these radicals may aggravate "reperfusion injury' in an ischemic animal model. Results of some of these studies were presented at the IV International Symposium on Blood Substitutes, 1991 in Canada. A manuscript describing some of the work has been published in Arch. Biochem. Biophys. Another manuscripts has been submitted for publication in Biochem. Biophys. Res. Comm.