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对比研究了牛血清蛋白(BSA)与部分水解的未改性聚丙烯酰胺(PAM-AA)、疏水改性聚丙烯酰胺(PAM-C12)和含有丙烯酸基团的疏水改性聚丙烯酰胺(PAM-C12-AA)之间的相互作用.等温滴定量热实验结果表明,除PAM-C12外,其他聚合物与BSA的结合焓均为放热,随AA含量的增加,放热焓值增大.与PAM和PAM-C12相比,PAM-C12-AA能够诱导BSA二级结构和微环境的明显变化,表明疏水性和电荷密度均对聚合物与BSA相互作用有重要影响.另外,不同浓度的PAM-C12-AA与BSA的作用方式不同,当聚合物的浓度略高于临界胶束浓度(CMC)时,由于聚合物的量较少,BSA分子改变其构型从而最大程度地与聚合物结合;当聚合物的浓度远高于CMC时,更多的聚合物链结合到BSA分子的正电荷“patch”上,PAM-C12-AA与BSA的紧密聚集体利于BSA二级结构的稳定.
The effects of bovine serum albumin (BSA) and partially hydrolyzed unmodified polyacrylamide (PAM-AA), hydrophobically modified polyacrylamide (PAM-C12) and hydrophobically modified polyacrylamide containing acrylic acid groups C12-AA) .The results of isothermal titration calorimetry showed that except for PAM-C12, the enthalpies of binding of other polymers to BSA were exothermic, with the increase of AA content, the exothermic enthalpy increased Compared with PAM and PAM-C12, PAM-C12-AA can induce significant changes of BSA secondary structure and microenvironment, indicating that both hydrophobicity and charge density have an important effect on the interaction of polymer with BSA.In addition, PAM-C12-AA behaves differently from BSA in that the BSA molecule changes its configuration to the maximum extent possible due to the small amount of polymer when the concentration of the polymer is slightly above the critical micelle concentration (CMC) ; When the concentration of polymer is much higher than that of CMC, more polymer chains are bound to the positive charge of “patch” of BSA molecule, and the close aggregation of PAM-C12-AA with BSA favors the secondary structure of BSA Stable.