等离子点pH(5.4)条件下,用平衡透析法和紫外光谱、荧光光谱、共振散射光谱研究了Ag(Ⅰ)与人血清白蛋白(bovine semm albumin,简称BSA)的结合.Scatchard图分析表明,Ag(Ⅰ)在HSA或BSA中有强弱两类结合部位,通过计算机拟合获得结合的逐级稳定常数值.紫外扫描发现Ag(Ⅰ)与HSA或BSA的结合存在滞后效应,表明Ag(Ⅰ)与HSA或BSA的结合可能诱导蛋白质构象发生缓慢变化(A~B),测得并讨论了这一构象变化的速度常数和活化参数.通过Ag(Ⅰ).HSA和Ag(Ⅰ)-BSA体系的紫外光谱,推测Ag(Ⅰ)与血清白蛋白中的硫结合形成直线型或近似直线型的配合物.利用荧光猝灭法计算出Ag(Ⅰ)-HSA和Ag(Ⅰ)-BSA体系的Stern-Volmer常数和双分子猝灭速率常数.共振散射光谱结果分析表明Ag(Ⅰ)的结合可使白蛋白分子趋于聚集.
This paper has minutely studied the interaction between Ag(Ⅰ) to human serum albumin (HSA) or bovine serum albumin(BSA) has been studied by equilibrium dialysis at pH(5.4). The Scatchard analysis indicates that there exists several strong binding sites of Ag(Ⅰ) in both HSA and BSA. A notable hysteretic effect has been observed in the interaction of Ag(Ⅰ) with HSA or BSA using UV-Visible spectrometry at pH(5.4), which shows that the binding between Ag(Ⅰ) with HSA or BSA may induce a slow transition of HSA or BSA from the conformation of weaker affinity for Ag(Ⅰ) to one of stronger affinity (A- B transition). The rate constants and activation parameters of this transition parameters were measured and discussed. The binding equilibrium has been also studied by resonance light-scattering spectrum(RLS) and flurescence quenching.