BSA与α-MnO_2及δ-MnO_2间的界面吸附作用

The adsorption of BSA on the surfaces of α-MnO_2 and δ-MnO_2

比较研究了牛血清白蛋白（BSA）与α-MnO2和δ-MnO2的界面吸附作用及其影响因素。结果表明，BSA在两种MnO2颗粒物表面有明显的吸附，且δ-MnO2比α-MnO2对BSA的吸附能力略强。pH3．8—8．0范围内，BSA在α-MnO2和δ-MnO2上的吸附率随pH的升高而减小，pH3．8条件下，α-MnO2上的吸附率为88．2％，δ-MnO2上的吸附率为94．0％。BSA在α-MnO2和δ-MnO2上的吸附量均随BSA浓度的增加而增大，吸附率随NaCl浓度的增加而减小。BSA在甜MnO2上的吸附具有很高的不可逆性，δ-MnO2上的吸附完全不可逆。吸附过程中BSA发生解螺旋作用，引起结构熵增大。

The adsorption of bovine serum albumin （BSA） on α-MnO2and δ-MnO2 was compared and the factors affecting its adsorption on the surfaces were investigated. The results showed that BSA significantly adsorbed onto α-MnO2 and δ-MnO2 surfaces, and the adsorption affinity of BSA on the surface of δ-MnO2 was higher than on that of α-MnO2. From pH 3.8 to pH 8.0, the percentage of BSA adsorbed on both particles was found to decrease as pH increased. At pH 3.8, the percentage of BSA adsorbed on α-MnO2 was 88.2% , while that of BSA on δ-MnO2 was 94.0%. The adsorption quantity of the protein on both particles increased with BSA concentration and decreased with NaC1 concentration. We also found that the adsorption process on α-MnO2 was quasi - reversible and the process on δ-MnO2 was completely irreversible. In the adsorption process, BSA undergo secondary structure transformation from α-helix to random coil, causing entropy increase.