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使用石英晶体微天平(QCM)研究了酪蛋白在聚苯乙烯、Au和SiO2三种芯片表面上的吸附与酶解行为.结果表明,酪蛋白在聚苯乙烯表面具有较高的非特异性吸附,吸附量为127.9ng/cm2,而在空白Au和SiO2表面几乎没有非特异性吸附.通过对Au和SiO2表面进行修饰和活化,酪蛋白可共价固定化在其表面,固定化量分别为178.0和1718.0ng/cm2.用胰蛋白酶对吸附的酪蛋白水解后,再用表面活性剂洗涤,可以完全去除聚苯乙烯表面的酪蛋白和其酶解产物,而单独使用表面活性剂仅能洗涤约36%吸附的酪蛋白.建立了用QCM测定胰蛋白酶在固液界面酶解酪蛋白酶活的方法,对共价固定化在修饰后Au和SiO2表面上的酪蛋白,胰蛋白酶的水解活性分别为0.010和0.157U/mg,远低于水解游离酪蛋白的17.8U/mg.
The adsorption and enzymatic behavior of casein on polystyrene, Au and SiO2 surfaces were studied by Quartz Crystal Microbalance (QCM). The results showed that casein has a high nonspecific adsorption on polystyrene surface, The adsorption capacity was 127.9ng / cm2, while there was almost no nonspecific adsorption on the blank Au and SiO2 surfaces.The casein could be covalently immobilized on the surface by immobilizing and activating the surface of Au and SiO2, the immobilization amounts were 178.0 and 1718.0ng / cm2. Casein hydrolyzed by trypsin, and then washed with surfactant, can completely remove the polystyrene casein and its enzymatic hydrolysis products, while the surfactant alone can only wash about 36 % Of casein adsorbed.It was established that QCM could be used to detect the activity of trypsin at the solid-liquid interface and the hydrolytic activity of trypsin on covalently immobilized Au and SiO2 surfaces was 0.010 And 0.157U / mg, much lower than 17.8U / mg of hydrolyzed free casein.