脱镁叶绿酸-a甲酯的合成及对牛血清白蛋白的结合作用

用荧光光谱和UV-Vis光谱研究了脱镁叶绿酸-a甲酯(Methyl pheo-phorbide-a)与牛血清白蛋白(Bovine Serium Albumin，BSA)的相互结合反应。实验表明叶绿酸-a甲酯与牛血清白蛋白的相互结合作用为单一的静态猝灭过程。在水溶液中脱镁叶绿酸-a甲酯发生自聚，它与蛋白质以表观摩尔比2∶1牢固结合，其结合常数K_B=6.7×104 L·mol-1。而在四氢呋喃与水的混合溶液中脱镁叶绿酸-a甲酯以单分子状存在, 其与BSA的结合摩尔比为1∶1。BSA分子与叶绿酸-a甲酯的结合点位为1。根据Frster非辐射能量转移机理，求算了给体(BSA)与受体(脱镁叶绿酸-a甲酯)间距离r=3.50 nm和能量转移效率E=0.39。

Study on the Interaction of Methyl Pheophorbide-a and Bovine Serum Albumins by Fluorescence

The binding reaction of methyl pheophorbide-a with bovine serum albumins (BSA) in aqueous solution was studied by fluorescence and UV-Vis absorption spectra. The results indicated that the combination reaction of them was a single static quenching process. In aqueous solution, methyl pheophorbide-a strongly bound BSA with the apparent molar ratio of 2∶1 because of methyl pheophorbide-a polymerized by itself. The binding constant K_B was 6.7×104 L·mol-1. In mixture solvent of tetrahydrofuran and water, methyl pheophorbide-a existed as single molecule and bound BSA with a molar ratio of 1∶1. There is single position for combining methyl pheophorbide-a with BSA. The shortest binding distance (r=3.50 nm) and energy transfer efficiencies (E=0.39) between donor (BSA) and acceptor (methyl pheophorbide-a) were obtained by Frster′s nonradiative energy transfer mechanism.