【摘要】 利用荧光光谱技术研究了6-硫鸟嘌呤(6-TG)和牛血清蛋白(BSA)之间的相互作用.6-硫鸟嘌呤对牛血清蛋白荧光的猝灭机制属于形成复合物的静态猝灭过程.在22,32和42℃下6-硫鸟嘌呤和牛血清蛋白之间的结合常数Ka分别为8.07×104,9.83×104和12.04×104L/mol,结合位点数n分别为1.002,1.022和1.039.3个温度下的热力学参数变化值(ΔH,ΔG和ΔS)表明,结合反应的主要作用力类型为疏水作用力,熵变化驱动该结合反应而焓变化不利于该结合反应.根据Forster非辐射能量转移理论,测得6-TG与BSA之间的结合距离r分别为3.44,3.52和3.54nm(22,32和42℃下).根据牛血清蛋白的结构,可以推测牛血清蛋白与6-硫鸟嘌呤结合的位点在ⅡA亚结构域,靠近Trp214的区域.更多还原

【Abstract】 Fluorospectroscopy techniques were employed to investigate the interaction of 6-thioguanine(6-TG) and bovine serum albumin(BSA).The experimental results indicate that the probable quenching mechanism of BSA by 6-TG is a static quenching procedure.The apparent binding constants Ka and the binding sites values n between 6-TG and BSA are 8.07×104 L/mol,1.002 (22℃),9.83×104 L/mol,1.022(32℃),12.04×104 L/mol,1.039(42℃),respectively.The thermodynamic parameters,such as ΔH,ΔG and ΔS,calculated at different temperatures indicate that hydrophobic forces play a major role when 6-TG interacts with BSA.The positive enthalpy(ΔH) and entropy(ΔS) value of the interaction of 6-TG and BSA indicate that the binding reaction is mainly entropy-driven and the enthalpy is unfavorable for it.Based on the Forster’s theory of non-radiation energy transfer,the binding distance,r between the donor(BSA) and acceptor(6-TG) is evaluated to be 3.44,3.52 and 3.54 nm at 22,32 and 42℃ respectively.According to the crystal structure of bovine serum albumin,it may be speculated that subdomain ⅡA is the binding site for the interaction of 6-TG and BSA,which is the region near Trp 214.更多还原