SELF ASSOCIATION OF COPPER(II) TETRAPHENYLPORPHINE IN LIPID BILAYERMEMBRANES

四苯基卟啉铜（II）（CuTPP）已被发现， 有利于分配成二肉豆蔻酰磷脂酰胆碱（DMPC） 囊泡 取向DMPC膜的EPR谱与 计算机模拟表明，CuTPP优先取向 分子平面垂直于双层表面， 低（小于或等于1/100）CuTPP/DMPC摩尔比。 然而，在这方面， 高（高）。 1/25）CuTPP/DMPC摩尔比， 分子变得与膜表面平行。 测量 CuTPP与硬脂酸的氮氧自由基之间的碰撞速率 位于膜中不同深度的酸自旋标记， 饱和恢复EPR谱导致的结论是， CuTPP取向的改变是自缔合的结果 在脂质双层中心附近的CuTPP分子的结晶。 自缔合过程取决于CuTPP/DMPC的摩尔比， 比例和样品制备后的时间。

Copper (II) tetraphenylporphine (CuTPP) has been found to partition favorably into dimyristoylphosphatidylcholine (DMPC) vesicles. EPR spectra of oriented DMPC membranes together with computer simulations show that the CuTPP is preferentially oriented with the plane of the molecule perpendicular to the bilayer surface at low (less than or equal to 1/100) CuTPP/DMPC molar ratio. However, for a high (ca. 1/25) CuTPP/DMPC molar ratio, the plane of the molecule becomes parallel to the membrane surface. Measurements of the collision rate between CuTPP and the nitroxide moiety of stearic acid spin labels located at different depths in the membrane using saturation recovery EPR spectroscopy led to the conclusion that the change of the CuTPP orientation is the result of self-association (crystallization) of CuTPP molecules near the lipid bilayer center. The self-association process depends both on the CuTPP/DMPC molar ratio and the time after sample preparation.