Equilibrium dialysis of metal-serum albumin (Ⅱ)——Allosteric effect in Ni(Ⅱ)-serum albumin systems

Detailed studies were carried out on equilibrium dialysis of the binding of Ni^(2+)+ion to human scrum albumin(HSA)and bovine serum albumin(BSA).The successive stability constants were obtained by the Icfisi squares fitting.The eight binding sites found for both Ni(Ⅱ)-HSA and Ni(Ⅱ)-BSA systems can be divided into two different sets;and for both systems,there exist two identical prior binding sites where the bound Ni^(2+)ions can he con sidered as allosteric effectors,which induce the allosteric effect in accordance with the model proposed by Moeod et al As indicated by allosteric parameters,the ability of R-state to bind Ni^(2+)ions is ca 100 times as much as that of T state,and the conformation of HSA is markedly tenser than that of BSA.