Cu~(2+)离子与蛋白质混合体系相互作用机制研究

应用荧光光谱法研究Cu2+离子与血清蛋白质混合组份体系的结合反应机制,测定了反应体系的结合常数K、结合位点数n,探讨了荧光猝灭机理。同时探索了Cu2+与蛋白质混合组份体系及单一组份体系相互作用的差异。结果表明:混合组份体系中,牛血清白蛋白(Bovine serum albumin,BSA)与牛乳铁蛋白(Bovine lactoferrin,BLF)分子间也存在着相互作用,从而影响混合组份体系中BSA/BLF与Cu2+的相互作用,Cu2+与蛋白质混合组份体系相互作用并非蛋白质单组份体系作用之和。分析实验数据,首次发现当BSA/BLF达到临界比值时,金属离子与混合蛋白质组份相互作用过程中出现了蛋白质分子的"契合"现象。文章利用生物酶反应机制中的酶活性部位柔性假说合理解释了Cu2+与血清蛋白质混合组份体系相互作用中的"量敏效应"。

Interaction Mechanism between Cu2+ and Mixed Protein System

Interaction mechanism between Cu2 + and BSA-BLF mixed protein system of different concentration ratios was investigated using fluorescence spectroscopy.The binding constant and binding sites were calculated and compared,the quenching mechanism were also discussed.Results indicated that the composition of bovine serum albumin(BSA)interacted with bovine lactoferrin(BLF),affecting the interaction mechanism between Cu2 + and BAS-BLF mixed protein system.Interaction strength between Cu2+ and SBA-BLF mixed protein system was not the single addition of that of Cu2+-BAS and Cu2+-BLF system.Through analyzing the experimental data,it was found that when composition ration of BAS-BLF mixed protein system reached the optimum value,the interaction between Cu2 + and BAS-BLF mixed protein system showed the coincidence phenomenon of proteins.Enzymatic activity theory of the enzyme reaction was used to explain the interaction mechanism,which called dosage-sensitization effect.