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我们曾用平衡透析方法研究了生理pH(7.43)下Zn(Ⅱ)与HSA(Human serum albumin,人血清白蛋白)或BSA(Bovine serum albumin,牛血清白蛋白)及Ni(Ⅱ)与HSA或BSA的相互作用。本文用平衡透析法结合原子吸收分光光度法研究了生理pH下Cu(Ⅱ)与HSA或BSA的结合情况。由于迄今报道的Cu(Ⅱ)与血清白蛋白的结合常数往往是用Scatchard公式或类似公式计算的,这实际上只反映了某种平均值,尚不足以全面反映结合状况。我们用非线性最小二乘法拟合Jjerrum方程,首次报道了Cu(Ⅱ)与血清白蛋白相互作用的逐级稳定常数值。结果表明:在相似条件下Cu(Ⅱ)与HSA或BSA结合平衡常数小于Zn(Ⅱ),而与Ni(Ⅱ)的数量级相似;平衡常数数量级为10~4mol~(-1)·dm~3左右;结合位置数HSA和BSA中均约有20个(计量值),分别分为二类和三类结合部位;其优先结合部位是His~3咪唑基N。用平衡透析方法证实在Cu(Ⅱ)-HSA及Cu(Ⅱ)-BSA体系中存在一个强的金属结合部位的推断。
We used the equilibrium dialysis method to study the effect of Zn (Ⅱ) and HSA (Human serum albumin, BSA (Bovine serum albumin) and Ni (Ⅱ)) and HSA BSA interaction. In this paper, the binding of Cu (Ⅱ) to HSA or BSA at physiological pH was studied by equilibrium dialysis and atomic absorption spectrophotometry. Since the binding constants of Cu (II) and serum albumin reported so far are often calculated using the Scatchard’s formula or the like, this actually reflects only some kind of averages and is not enough to fully reflect the binding status. We fit the Jjerrum equation with the nonlinear least square method, and we first reported the step-by-step stability constants of the interaction between Cu (Ⅱ) and serum albumin. The results show that the equilibrium constant of Cu (Ⅱ) with HSA or BSA is less than that of Zn (Ⅱ) under the similar conditions, but similar to that of Ni (Ⅱ); the order of equilibrium constant is 10 ~ 4mol ~ (-1) , And about 20 binding sites (HSA and BSA), which are divided into two types and three types of binding sites respectively; the preferred binding sites are His ~ 3 imidazolyl N; The equilibrium dialysis method was used to confirm the existence of a strong metal-binding site in Cu (II) -HSA and Cu (II) -BSA systems.