谷氨酰胺转氨酶热稳定剂优化

摘要

Transglutaminase (EC 2.3.2.13,TGase) can catalyze the cross-linking of protein molecules,and it has been widely used in the fields of food,biology,medicine,textile and so on.In order to improve the thermal stability,the effects of carbohydrates,salts and alcohols on the half-life of TGase at 55 ℃ ((t1/2 (55 ℃)) were studied.The results showed that the addition of sorbitol,wheat protein,NaCl and glucose could effectively prolong the half-life of TGase.On this basis,orthogonal experiments were carried out to obtain the best compound stabilizer:50 g/L sorbitol,50 g/L wheat protein,50 g/L NaCl,and 50 g/L glucose.Under the protection of the compound stabilizer,the t1/2 (55 ℃) value and the optimum reaction temperature of TGase were increased by 59.73-fold and 10 ℃ respectively compared with the control (no stabilizer),and the residual enzyme activity rate after storage at room temperature (25 ℃) for 80 days was 73.84％,62.79％ higher than the control.The results of this study will facilitate the improvement of TGase production and application development.%谷氨酰胺转氨酶(Transglutaminase,TGase)能够催化蛋白质分子发生交联,被广泛应用于食品、医药和纺织等领域.为提高其热稳定性,研究了糖、盐及醇类等稳定剂对TGase在55℃下的半衰期[t1/2(55℃)]的影响.结果表明,山梨醇、小麦蛋白、NaCl和葡萄糖能延长TGase的t1/2(55℃).在此基础上进行正交实验,获得最佳的稳定剂配方:山梨醇50 g/L、小麦蛋白50 g/L、NaCl 50 g/L、葡萄糖50 g/L.在该复合稳定剂保护下,TGase的t1/2(55℃)和最适反应温度较对照(无稳定剂)分别提高59.73倍和10℃;室温(25℃)储存80 d的残余酶活率为73.84％,较对照提高62.79％.此研究结果将促进TGase的生产改进和应用拓展.