CHARACTERIZATION OF PHOTOOXIDIZED PLASMENYLCHOLINES

拟议研究的主要目标是量化光氧化的血浆胆碱的形成率，并表征其对膜流动性和脂质介导的膜融合性的影响。提出了一个跨学科的项目，涉及脂质合成，HPLC分析与电化学和质谱检测，囊泡泄漏，EPR脂质扩散实验，旨在了解光氧化对膜通透性的影响。 水溶性和膜溶性敏化剂，纳入客体膜囊泡，将在有氧条件下照射，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的观察结果进行比较。将使用由Rui & Thompson [Chem.Eur. J. 1996 2 1505]。将使用HPLC分析和膜融合荧光测定来监测脂质光氧化、囊泡脂质混合和囊泡内容物混合的速率（作为照射时间和致敏剂类型的函数）。 还将使用31P NMR和EM技术对触发前后的膜结构进行物理表征。这些实验将深入了解乙烯基醚连接的甘油磷脂，如血浆胆碱和血浆乙醇胺，可能参与再灌注损伤，多发性硬化症和其他脱髓鞘疾病的氧化机制。

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.