CHARACTERIZATION OF PHOTOOXIDIZED PLASMENYLCHOLINES

本研究的主要目的是量化光氧化plasmenylcholines的形成速率，并表征其对膜流动性和脂质介导的膜原性的影响。为了解光氧化对膜通透性的影响，拟开展跨学科的脂质合成、电化学和质谱检测的高效液相色谱分析、囊泡渗漏和EPR脂质扩散实验。水溶性和膜溶性敏化剂，纳入客膜囊泡，将在有氧条件下被照亮，以确定敏化剂定位对脂质光氧化速率的影响。这些实验的结果将与使用化学氧化剂所作的观察结果进行比较。标记的plasmenylcholines将使用Rui和Thompson [Chem]开发的方法合成13C NMR实验。欧元。[j]。HPLC分析和膜融合荧光法将用于监测脂质光氧化率、囊泡脂质混合率和囊泡内容物混合率与照射时间和增敏剂类型的关系。触发前后膜结构的物理表征也将使用31P NMR和EM技术进行。这些实验将深入了解乙烯醚连接甘油磷脂的氧化机制，如浆门酰胆碱和浆门酰乙醇胺，它们可能涉及再灌注损伤、多发性硬化症和其他脱髓鞘疾病。

The primary objectives of the proposed research are to quantify the formation rates of photooxidized plasmenylcholines and characterize their impact on membrane fluidity and lipidmediated membrane fusogenicity. An interdisciplinary project is proposed involving lipid synthesis, HPLC analysis with electrochemical & mass spectrometric detection, vesicle leakage, and EPR lipid diffusion experiments aimed at understanding the effects of photooxidation on membrane permeability. Water-soluble and membrane-soluble sensitizers, incorporated within guest membrane vesicles, will be illuminated under aerobic conditions to determine the effects of sensitizer localization on the lipid photooxidation rate. Results from these experiments will be compared with observations made using chemical oxidants. Labeled plasmenylcholines will be synthesized for 13C NMR experiments using methodology developed by Rui & Thompson [Chem. Eur. J. 1996 2 1505]. HPLC analysis and membrane fusion fluorescence assays will be used to monitor the rates of lipid photooxidation, vesicle lipid mixing, and vesicle contents mixing as a function of irradiation time & sensitizer type. Physical characterization of the membrane structures, before and after triggering, will also be performed using 31P NMR and EM techniques. These experiments will yield insights into the oxidative mechanisms of vinyl ether linked glycerophospholipids, such as plasmenylcholine and plasmenylethanolamine, that may be involved in reperfiision injury, multiple sclerosis, and other demyelinating disorders.