【摘要】 利用药物对蛋白的荧光猝灭作用,用荧光法研究了N-苯酰甲噻唑溴(PTB)与牛血清白蛋白(BSA)及人血清白蛋白(HSA)的相互作用。测定发现BSA溶液的最大激发波长为280nm,HSA溶液的最大激发波长为290nm。分别向溶液中加入PTB后,原有的最大发射波长处的强度明显减弱。说明PTB对BSA和HAS有荧光猝灭作用。PTB与BSA,HSA有中等强度的结合。测得15℃时PTB与BSA,HSA的结合常数分别为3.66×103和3.83×103,结合位点数n分别为1.02和1.16;37℃时PTB与BSA,HSA的结合常数分别为3.58×103和3.35×103,结合位点数分别为0.95和0.87。根据热力学常数确定了PTB与BSA,HSA之间的主要作用力类型均为静电作用力。通过Fster偶级-偶级非辐射能量转移原理,得到BSA,HSA与PTB结合的位置距色氨酸残基的距离分别为7.5和7.9nm。根据白蛋白的结构,可以推测BSA,HSA与PTB结合的位点在ⅡA亚结构域,靠近Try214的区域。更多还原

【Abstract】 A molecular spectroscopic investigation of the interaction of phenacyl thiazolium bromide(PTB)and bovine serum albumin(BSA)or human serum albumin(HSA)is reported employing fluorescence quenching techniques.It is determined that the maximal excitation wavelength is 280 nm for BSA solution,and 290 nm for HAS solution.When PTB was added into these solutions gradually,the emission peaks were decreased obviously,which are typical quenching phenomena.The results obtained reveal that there is a medium-intensity binding affinity for PTB with HSA and BSA.At 15 ℃,the binding constants of PTB and BSA(HSA)are 3.66×103 and 3.83×103,and the numbers of binding sites are 1.02 and 1.06 respectively.At 37 ℃,the binding constants of PTB and BSA(HSA)are 3.58×103 and 3.35×103,and the numbers of binding sites are 0.95 and 0.87 respectively.According to the thermodynamic parameters,the main sort of the binding force between the drug and BSA or HSA was electrostatic force.Based on the Fster non-radiation energy transfer theory,it could be acquired that the distance between BSA or HSA and PTB is 7.5 or 7.9 nm.According to the crystal structure of serum albumin,it can be speculated that subdomain ⅡA was the binding sites for the interaction of PTB and serum albumin,which is the region near Try214.更多还原