【摘要】 作者合成了阴离子型和阳离子型葡聚糖,以此为载体,用CNBr活化其剩余羟基,固定化了葡萄糖淀粉酶和葡萄糖异构酶。就离子型载体对固定化酶的蛋白载量、最适pH和热稳定性等的影响做了考察。发现固定化酶的蛋白载量不仅与载体的电性质有关,也与酶分子自身的电性质有关。当载体电性质与酶蛋白电性质相反时,固定化酶的蛋白载量增加,热稳定性提高、载体电性质与酶蛋白电性质相同时,固定化酶的蛋白载量不变或下降,其热稳定性不变。作者还发现当离子型载体孔度和体系缓冲液浓度一定时,酶分子能否进入多孔性载体内部,对其最适pH是否变化影响极大。若酶分子仅被连接在载体的外表层,其最适pH不发生变化,反之亦然。作者还观察到当多糖类载体引入氨基或羧基后,大大增强了其抵抗微生物侵蚀的能力。更多还原

【Abstract】 Anionic and cationic Sephadex were prepared and the glucoamylase and glucose isomerase were immobilized to these carriers by CNBr.The effects of ionic carriers on protein binding capacity (PBC)optimal pH and thermal stability of the immobilized enzymes (IE) were studied. We discovered that the PBC of the IE is related not only to the acid-base property of the carriers, but also to those of the enzymes.If the carrier has opposite electric charge to that of the enzyme, the PBC and the thermal stability of the IE will increase, if the carrier and enzyme have the same kind of electric charge, the PBC of the IE either remaing unchange or decreases. We also discovered that when the porosity of the ionic carriers and the concentration of the buffer were constant, if the enzyme was only coupled to the carriers’outer surface, the IE’s optimal pH would not change; and if most of the enzyme was coupled to the carriers’ internal surface, the IE’s optimal pH would probably change. We noted that after the carboxyl groups and amino groups were introduced to Sephadex, the resistance of the carrier to microbial contamination was largely increased.更多还原