米曲霉F-81产中性蛋白酶的固定化条件及其特性

以海藻酸钠为载体,戊二醛为交联剂固定化米曲霉F-81产中性蛋白酶,研究了固定化条件及固定化酶的性质。结果表明,固定化的最佳条件为:固定化时间1 h、海澡酸钠浓度4%、戊二醛浓度9%、CaCl2浓度0.7 mol/L。在此条件下固定化的中性蛋白酶活力为游离酶活力的68%。固定化酶的最适作用温度为65℃,最适作用pH值为7.0。60℃下酶稳定性较好,80℃下处理60 min,粗酶中几乎检测不到酶活力;中性蛋白酶pH稳定范围为6.5-9.5。Km值为24.83 mg/mL,最大反应速率Vmax为0.043 12 mg/min。

Immobilization Conditions of Neutral Protease from Strain Aspergillus oryae F-81 and Its Characteristics

Neutral protease from Aspergillus oryaze F-81 was immobilized using sodium alginate as the carrier and glutaraldehyde as the crosslinking agent.The best conditions for immobilization and the characteristics of the immobilized neutral protease were studied.The results showed that the best efficiency of immobilization was obtained while immobilized time was 1 h,sodium alginate concentration was 4% and glutaraldehyde concentration was 9% with 0.7 mol/L CaCl2.Under these conditions,the relative activity for immobilized neutral protease to the free one was 68%.The optimum temperature and pH for neutral protease catalysis were 65℃ and 7.0,respectively.The immobilized enzy-me was more stable at 60℃ than its unimmobilized counterpart,while its activity almost could not be detected after being treated at 80℃ for 60 minutes.The stable pH range for immobilized neutral protease were 6.5-9.5.The Km and Vmax were 24.83 mg/mL and 0.043 12 mg/min,respectively.