无花果蛋白酶在阴离子交换树脂上的固定化

Studies on Immobilization of Ficin on Anion Exchange Resin GM 201

无花果蛋白酶通过８％戊二醛活化载体，共价结合到聚苯乙烯阴离子交换树脂ＧＭ２０１上，固定化作用在ｐＨ７．７，酶浓度０．８ｍｇ／ｇ树脂，４℃下进行６ｈ。得到的固定化酶表观Ｋ_ｍ值（酪蛋白，１．１１×１０^（－４）ｍｏｌ／Ｌ）小于溶液酶Ｋ_ｍ值（１．９６×１０^（－４）ｍｏｌ／Ｌ）；固定化酶活性在ｐＨ６～８保持稳定，溶液酶最适ｐＨ为７．２；固定化酶最适温度由溶液酶的５０～６０℃移至３７℃；固定化酶２５℃保持７ｄ，重复水解酪蛋白７次后，保留８３．３％活性。固定化酶对酪蛋白水解度达４７．５％，对大豆球蛋白达１１．６％。

Ficin was covalently immobilized to the carrier, anion exchange resin GM201, by activating the carrier with glutaraldehyde. The immobilization was performed at PH7.7, 4℃,for 6h using enzyme concentration 0. 8 mg/g resin. The resulting immobilized enzyme has an apparent Km of 1.11×10￣(-4) mol/L for action on casein as compared to 1.96×10￣(-4) mol/L by soluble enzyme. The optimal pH range of immobilized ficin became much broader, changing from PH7.2 for soluble enzyme to pH6￣8, at which the activity of immobilized enzyme remained stable. The optimal temperture changed from 50￣60℃ for soluble enzyme to 37℃ for the immobilized enzyme. After it was stored at 25℃ for 7 days, the immobilized ficin retained approximately 83.3% of its original activity after 7 rounds of reaction using casein as substrate. The degree of hydrolysis was 47.5% for casein and 11.6% for soybean protein.