不同代PAMAM树状大分子与牛血清白蛋白的相互作用研究

Study on the Interactions of Different PAMAM Dendrimers with Bovine Serum Albumin

采用发散法合成了以乙二胺为核的聚酰胺-胺型(PAMAM)树状大分子,并应用荧光光谱法研究了生理条件下(pH=7.4)3.0代(G3.0)、3.5代(G3.5)和4.0代(G4.0)PAMAM树状大分子与牛血清白蛋白(BSA)的相互作用.结果表明,三种PAMAM树状大分子都能引起牛血清白蛋白荧光猝灭,其程度主要取决于各自末端基团的性质,猝灭机制属于静态猝灭.G4.0PAMAM,G3.5PAMAM和G3.0PAMAM与BSA的猝灭常数分别为2.73,1.69,1.55L·mmol-1.同时考察了体系pH值及离子强度的变化对PAMAM与BSA相互作用的影响.此外,同步荧光和紫外光谱法(UV)以及红边激发荧光位移(REES)等方法的研究结果表明,PAMAM树状大分子的存在改变了BSA的构象.

Polyamidoamine （PAMAM） dendrimers have been synthesized by divergent with ethylenediamine as core. The interaction between PAMAM including amine-terminated generation 4.0 （G4.0）、 generation 3.0 （G3.0） PAMAM and ester-terminated generation 3.5 （G3.5） PAMAM dendrimers and bovine serum albumin （BSA） under physiological condition was studied by fluorescence spectroscopy. The results showed that the fluorescence intensity of BSA decreased with the addition of different PAMAM dendrimers,the quenching extent strongly depends on the type and amounts of their surface groups. The quenching mechanism was static quenching mechanism. The quenching constants of G4.0 PAMAM,G3.5 PAMAM,G3.0 PAMAM with BSA were 2.73,1.69,1.55 L·mmol-1,respectively. The influence of pH and ionic strength on the interactions was also investigated. Furthermore,synchronous fluorescence,ultraviolet-visible spectra analysis （UV）,and red edge excitation shift （REES） showed that PAMAM dendrimers could change the conformation of BSA.