一种新型脂肪酶的反应特性及动力学研究

Research on Enzymatic and Kinetic Characteristics of a New Lipase

摘要:

本文对一种具有高度特异磷脂酶活力的新型脂肪酶的反应特性和动力学进行了研究。此酶可同时作脂肪酶和磷脂酶使用。作脂肪酶使用时，始初时酶活最高的条件是：pH值为7.0，温度为40 ℃；作磷脂酶使用时，始初时酶活最高的条件是：pH值为5.0，温度为60 ℃。该酶在pH 4.0~9.0范围内稳定，50 ℃时稳定性较好，其水解甘油三酯的酶活24 h为79.80%，水解磷脂的酶活24 h为61.1%；60 ℃时酶活的稳定性变差，其水解甘油三酯的酶活15 min为原酶的17%；水解磷脂的酶活1 h为原酶的26.39%，5 h为13.89%。对其动力学和热力学常数进行了测定和计算，得知在各自始初酶活最高的条件下该酶对磷脂的催化效率高于对甘油三酯的催化效率。脱胶实验验证此酶可用于菜籽油脱胶。

Abstract:

The enzymatic and kinetic properties of a new lipase with high specific phospholipase activity were explored in this work .It can catalyze the hydrolysis of both lipids and phospholipids. For its lipase activity, the optimum pH value and temperature were 7.0 and 40 ℃, respectively, while the best pH value and temperature for its phospholipase activity were 5.0 and 60 ℃, respectively. The enzyme was stable within the pH value range of 4.0~9.0 and at 50 ℃. Its lipase activity and phospholipase activity reduced to 79.80% and 61.1% respectively at 50 ℃ for 24 h. However, it was found unstable at 60 ℃ as only 17% of its lipase activity remained at 60 ℃ for 15 min and its residual phospholipase activity at 60 ℃ for 1 h and 5 h were found to be 26.39% and 13.89%, respectively. The kinetic and thermodynamic parameters for the lipase catalyzed reactions were determined and the results indicated that the catalysis efficiency of the enzyme in triglyceride hydrolysis was higher than that in phospholipids hydrolysis, which was demonstrated by its capability in catalyzing the degumming of rapeseed oil.