As(Ⅲ)和As(Ⅴ)与牛血清白蛋白的结合平衡研究

在模拟动物体生理条件下,研究As(Ⅲ)和As(V)与牛血清白蛋白(BSA)的相互作用.用氢化物发生-超低温捕集-原子吸收分光光度法测定平衡透析后As(Ⅲ)或As(V)的浓度,用Scatchard方法分别处理实验数据,确定结合部位和结合常数.发现当As(Ⅲ)浓度(cAs(Ⅲ)∶cBSA≤1∶1)较低时,在BSA中有1.3个强结合部位,结合常数为1.7×106,为强结合;当As(Ⅲ)的浓度(cAs(Ⅲ)∶cBSA≥2∶1)较高时,没有明显的特征结合点,表现为弱结合.而As(V)与BSA无任何结合作用.

Binding Equilibrium Between As(Ⅲ) or As(Ⅴ) and Bovine Serum Albumin

Under the imitated physiological condition of animal body,the binding of As(Ⅲ) or As(V) to bovine serum albumin(BSA) was studied.Arsenic species were detected with hydride generation trapping by ultra-hypothermia coupled with atomic absorption spectrometry.The binding plots analysis indicated that the binding model was similar to Scatchard model when the concentrations of As(Ⅲ) ions were lower(cAs(Ⅲ)∶cBSA≤1∶1),there were 1.3 strong binding sites of As(Ⅲ) ions in BSA,the stability constants was 1.7×106.The binding model was unsimilar to Scatchard model when the concentrations of As(Ⅲ) ions were higher(cAs(Ⅲ)∶cBSA≥2∶1),and As(V) ions had litter effect on BSA.