Pb2+与HSA或BSA的结合平衡研究

用平衡透析法详细研究了模拟生理pH值为6．3条件下，Pb^2＋与人血清白蛋白（HSA）或牛血清白蛋白（BSA）的结合平衡。Scatchard图分析表明，Pb^2＋在BSA和HSA中分别有1．6和1．8个强结合位点，通过非线性最小二乘法拟合Bierrum方程，得到了Pb^2＋-HSA体系和Pb^2＋-BSA体系的逐级稳定常数，其中K1，K2均明显大于其余K值。Hill系数分析表明，Pb^2＋与HSA或BSA的结合存在弱负协同效应。

Study on binding equilibrium between Pb2+ and HSA or BSA

The binding of Pb~(2+) to human serum albumin(HSA) or bovine serum albumin (BSA) has been studied by equilibrium dialysis at pH 6. 3. Scatchard analysis indicates that there are 1. 6 and 1. 8 strong binding sites for Pb2+ in BSA and HSA, respectively. The successive stability constants for the Pb~(2+)-HSA and Pb~(2+)-BSA systems are determined by non-linear least-square method fitting Bjerrum formula. Of these stability constants, K_1 and K_2 are obviously higher than the values of the other stability constants. The analysis of Hill plot indicates that there exists weak negative cooperative effect in both Pb~(2+)-HSA and Pb~(2+)-BSA systems.