BIOLOGICAL CONSEQUENCES OF PROTEIN OXIDATION

蛋白质氧化的生物学后果

• 批准号: 5200787
• 负责人: E B SHACTER
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5200787
• 关键词: aldehydes; carbonyl compound; disulfide bond; free radical oxygen; human tissue; ketones; metabolism; neutrophil; oxidation; phenylhydrazines; protease inhibitor; protein metabolism; proteins; proteolysis; western blottings; xanthine oxidase

Proteins can become oxidized under a variety of conditions in vitro and in vivo. Specific polypeptide changes include formation of aldehyde (carbonyl) groups, generation of methionine sulfoxide and dityrosine, rearrangement of disulfide bonds, cleavage of peptide bonds, and protein aggregation. The consequences of protein oxidative modifications are varied. Some modifications lead to differential susceptibility of a protein to proteolytic cleavage while others cause gain or loss of biological activity. For example, we have found that oxidative modification of fibrinogen inhibits ability of the protein to undergo clotting. Conversely, oxidation of plasma protease inhibitors can lead to an increase of clotting activity. Our research is designed to elucidate the conditions under which proteins acquire oxidative modifications and to ensure that the assays employed provide a correct assessment of the types of modifications incurred. In recently completed experiments, we determined that the carbohydrate moieties of glycoproteins do not undergo oxidative modification to carbonyl groups under conditions that oxidize amino acid side chains. In addition, we validated the use of a Western blot assay for protein carbonyls for use on glycoproteins. Currents studies are aimed at determining the extent to which proteins undergo oxidative modification within cells exposed to varying growth conditions, including oxidative stress. Because cellular lipids are also targets for oxidative attack and can modify proteins through conjugation reactions, it will be important to distinguish between lipid-derived protein modifications and direct protein oxidative modification. Assays to accomplish this are currently being developed.

蛋白质在体外可以在各种条件下被氧化， 在活体内。特定多肽的变化包括醛的形成 (羰基)基团，甲硫氨酸亚砜和二叔丁基的生成， 二硫键重排、多肽键断裂和蛋白质 聚合。蛋白质氧化修饰的后果是 多种多样。一些修改导致了一种 蛋白质到蛋白水解性切割，而其他导致得或失 生物活性。例如，我们已经发现氧化 纤维蛋白原的修饰抑制了蛋白质的能力 凝血。相反，血浆蛋白水解酶抑制物的氧化可导致 凝血活性的增加。我们的研究旨在 阐明蛋白质获得氧化的条件 修改并确保所采用的分析提供正确的 对所发生的修改类型的评估。在最近完成的 实验，我们确定了碳水化合物的部分 糖蛋白不会被氧化修饰成羰基。 在氧化氨基酸侧链的条件下。此外，我们 验证了蛋白质羰基的蛋白质印迹分析的使用 在糖蛋白上。目前的研究旨在确定 暴露在细胞内的蛋白质会经历氧化修饰 不同的生长条件，包括氧化应激。因为蜂窝 脂类也是氧化攻击的目标，可以修饰蛋白质 通过共轭反应，区分 脂源性蛋白修饰与蛋白质直接氧化 修改。实现这一目标的分析方法目前正在开发中。