以卵清蛋白为载体的固定化木瓜蛋白酶的制备及其性质

以变性的卵清蛋白为载体, 用戊二醛为交联剂固定木瓜蛋白酶. 通过正交实验考察了固定化pH值、 交联剂戊二醛浓度、 交联时间和酶用量对固定化木瓜蛋白酶活力的影响,确定了最适固定化条件： 5%戊二醛, pH 6.0, 交联时间20 h, 每克载体含酶量12 mg. 对比研究了游离木瓜蛋白酶和固定化木瓜蛋白酶的性质, 所得到的固定化木瓜蛋白酶最适温度90 ℃, 最适pH 9.0, 米氏常数53.6　mg/mＬ, 其热稳定性及耐热性均较游离酶显著提高.

Preparation and its properties of the immobilized papain with denatured egg white protein as the support

Papain was immobilized on a denatured egg white protein as the support with glutaraldehyde as the cross-linker. The effects of pH, the concentration of glutaraldehyde, time and the amount of the enzyme on the activity of the immobilized papain were examined through the experiments of orthogonal test. The optimal condition for the immobilization was set up, i.e., glutaraldehyde concentration is 5%; pH 6.0; the quantity of enzyme used 12 mg/(g support) and the reaction time 20 h. At the same time, the comparative study on the properties of free and immobilized p apain was made. The optimal temperature and pH are 90 ℃ and 9.0, respectively . The K_m for the immobilized enzyme is 53.6 mg/mL. The thermostability and thermotolerance of the immobilized enzyme are obviously increased compared to those of the free one.