【摘要】 提取并纯制了人红细胞收缩蛋白(SP),用荧光滴定,园二色散(CD)谱研究了稀土离子Ln3+与SP的作用。Scatchard法解析表明,每个收缩蛋白四聚体分子有870个Eu3+离子的结合部位,其中290个为强结合部位,其K1=5.8×105L·mol-1;其余580个为弱结合部位,其K2=3.3×104L·mol-1。Ln3+与SP的结合导致SP的构象改变,这种改变既与Ln3+与SP的浓度比有关,也与稀土的性质有关。更多还原

【Abstract】 The human erythrocyte spectrin （SP） was isolated and purified. The interaction of SP and rare earth ions (Ln³⁺) was studied by fluorescence titration and circular dichroism （CD） spectra. On the basis of Scatckard plot, there are 870 binding sites of Eu³⁺ ions per spectrin tetramer. Among them, 290 sites （n₁） with binding constant K₁=5.8×10⁵ L·mol^-1 are high-affinity, the remaining sites （n₂=580） are low-affinity, K₂=3.3×10⁴ L·mol^-1. The binding of rare earth ions (Ln³⁺) to spectrin induces the conformation change of spectrin, and the change dependes both on the ratio of concentrations of Ln³⁺ ions to spectrin and nature of Ln³⁺ ions.更多还原