静电作用与修饰铜锌超氧化物歧化酶的稳定性

Electrostatics and Stability of Modified Copper,Zinc Superoxide Dismutase

铜锌超氧化物歧化酶（Ｃｕ，Ｚｎ－ＳＯＤ）表面的赖氨酸经化学修饰后，酶的稳定性显著提高．赖氨酸被修饰后，酶的电荷结构遂发生变化，从而影响到酶分子电场．使用ＦＤＰＢ方法（有限差分法求解Ｐｏｉｓｓｉｏｎ－ＢＯｌｔｚｍａｎ方程）计算了酶修饰前后的静电场变化，以及对维持酶的结构稳定起重要作用的Ｃｕ，Ｚｎ配位结构的影响结果表明，Ｃｕ，Ｚｎ配位体的两级离解常数在酶修饰后分别约下降１０３，１０６．

After the lysines on the surface ofCu;Zn superoxide dismutase are modified;theenzyme stability increases remarkably.The rearrange of charge structure of the enzyme due tomodification results in the change of enzymeelectrostatic field.The finite difference solutionto the Poisson-Boltzman method is used tocalculate the change of electrostatic field and theeffect on Cu; Zn ligand structure which play animportant role to stabilize the enzyme.Theresults show the first and second decompositionconstants of Cu; Zn ligand complex are reducedby 103 and 106 after modification respectively.