脂肪酶水解壳聚糖作用研究

通过还原端基含量测定、粘度测定研究了脂肪酶非专一性对壳聚糖的降解作用,探索了酶反应过程中温度、pH、加酶量、底物浓度、反应时间、金属离子等因素对脂肪酶降解壳聚糖的影响,以及不同脱乙酰度和不同分子量的壳聚糖与脂肪酶降解反应的关系。结果表明,以壳聚糖为底物的脂肪酶的一些催化特性为最适温度50～55℃,最适pH5～5.5,反应时间在3～4h范围内;降解作用随着酶用量和底物浓度的增加而增加,水解反应不符合Michaelis-Menten方程;3mmol/L的Cu2+,10mmol/L的Mg2、Ca2+对脂肪酶有一定的激活作用,10mmol/L的Ba2+、Zn2+、Fe3+对该酶有一定的抑制作用,随着底物壳聚糖脱乙酰度的提高,降解速度降低。

The effects of reaction temperature, pH, amount of enzyme, substr ate co ncentration and time on the hydrolysis of chitosan by lipase were studied. The r elationship between hydrolysis and structure of chitosan by lipase was discussed . The optimum temperature and optimum pH were 50～55℃ and 5.0～5.5 respectively . The reaction did not conform to the Michaelis-Menten. 10mmol/L Mg2+,Ca2+,and 3 mmol/L Cu2+ could increase enzyme activity, but 10mmol/L Fe3+,Zn2+,Ba2+ inhibite d enzyme activity. The increasing of N-acetylate chitosan leaded to the slowdown of degradation.