【作者】 边贺东；

【导师】 梁宏；

【作者基本信息】 广西师范大学 ， 有机化学， 2000， 硕士

【摘要】 用平衡透析法详细研究了pH7.43条件下Co（Ⅱ）及pH 63条件下La（Ⅲ）与HSA（humanserumalbumin）或BSA（bovineserurnalbumin）的结合平衡及其与Cu（Ⅱ）、Zn（Ⅱ）或Ca（Ⅱ）等的竞争。Scatchard图分析表明，co（Ⅱ）在HSA和BSA中均有3个强结合部位，分别有12和15个弱结合部位，La（Ⅲ）在HSA和BSA中均有2个强结合部位，分别有8和6个弱结合部位。通过非性最小二乘法拟合Bjerrurm方程得出Co（Ⅱ）-HSA、Co（Ⅱ）-BSA及La（Ⅲ）-HSA、La（Ⅲ）-BSA体系的逐级稳定常数值，其K₁的数量级为10⁴。Co（Ⅱ）-HSA、La（Ⅲ）-HSA的逐级稳定常数分别大于Co（Ⅱ）-BSA和La（Ⅲ）-BSA的。通过Co（Ⅱ）与Cu（Ⅱ）、Zn（Ⅱ）、Ca（Ⅱ）等的竞争结合HSA或BSA的结果，推测Co（Ⅱ）在HSA或BSA中的一个强结合部位可能位于HSA或BSA分子的N-端三肽段上，呈八面体构型：一个强结合部位可能位于HSA或BSA分子的内部，涉及2-3个咪唑基氮原子和1-2个羧基氧原子，呈四面体构型；另一个强结合部位的配位原子可能全是氧原子。从La（Ⅲ）与Cu（Ⅱ）、Zn（Ⅱ）、Cd（Ⅱ）等的竞争结合HSA或BSA的结果推测：La（Ⅲ）在HSA或BSA中的一个强结合部位的配位原子可能全部是氧原子。Hill系数及自由能偶合分析表明Co（Ⅱ）在HSA或BSA的结合均产生一定的正协同效应(Co（Ⅱ）-HSA体系，h_max=2.7;Co（Ⅱ）-BSA体系h_max=1.4)，Co（Ⅱ）与HSA结合的正协同效应大于与BSA的结合。La（Ⅲ）与HSA或BSA的结合均产生一定的负协同效应CEa（Ⅲ）-HSA，h_max=0.83；La（Ⅲ）-BSA，h_max=0.88)。更多还原

【Abstract】 The binding of Co(ll)and La(Lll) to human serum albumin (HSA) or bovine serum albumin(BSA) and the compection with Cu(ll), Zn(ll) or C~ll) have been studied by equilibrium dialysis at physiological pH(7.43) and pH(6.30), respectively. The Scatchard analysis indicates that there are three strong binding sites, 12 and 15 weak binding sites of Co( II) in HSA and BSA, respectively; and there are 2 strong binding sites, S and 6 weak binding sites of La(Ill) in HSA and BSA ,respectively. The successive stability constants of Co( II) -lISA , Co( II) -BSA , La(llI)-HSA and L.a(III)-BSA are obtained by non-linear least-square method fitting Bjemim formula. The order of magnitude of k1is found to be 1O~. The successive stability constants of Co( Ii) -HSA and La(IIl)-HSA are greater than that of Co( II) -BSA and L.a(llI)-BSA The results of the compectition between Co( II) and Cu( II), Zn( II) or Ca( II )indicate that one of the strong binding sites of Co( II) in HSA or BSA is most probably located at the tripeptide segment of N-terminal sequence of HSA and BSA taking octahedral configuration. Another binding site is located inside of the protein. The coordinated atoms are two or three Nitrogen atoms of imidazole and one or two oxygen atoms of carboxyl, that take tetrahedral configuration. The last one is coordinated with almost all oxygen atoms. Judged from the compectidon between La(llI) and Cu( II), Zn( II) or Cd( II), One of the strong binding sites of La(IIJ) in HSA or BSA is most probably coordinated with almost all oxygen atoms. The analyses of Hill plots and free energy coupling show that the binding of Co( II) to HSA and BSA results some positive cooperative effect (Co( II )-HSA system, h,.~=2.7:Co( 11 )-BSA, h,,~=1 .4), and the former is greater than the latter. In La(llI)-HSA and La(llI)BSA systems, there are some negative cooperative effect (La(llI)-HSA system, h=O.83 and更多还原