PVA降解酶催化反应的动力学方程

摘要

The properties and catalytic reaction kinetics of PVA-degradation enzyme from a newly selected mixed strain that is able to fully degrade PVA were studied for its actual use. Through the determination of changes in enzymatic activities in the course of the PVA degradation process, a catalysis kinetic equation was assumed first and then verified. The results indicated that the enzymatic activities would get lower along with the PVA degradation efficiency rising when PVA was not yet completely degraded. After the degradation was completed, the enzymatic activities tended to keep at certain level. As the PVA concentration increased, the enzymatic activities enhanced gradually. Michaelis constant Kr, of PVA-degradation enzyme was 2.06×10^-3 mol/L and the highest reaction rate Vr~,x was 19.5 units per minute. Thus, the kinetic equation on the catalytic reaction could be obtained as V=19.5 [S] / (2.06×10^-3+[S]).%筛选了1种能够完全降解PVA的混合菌系,对其所生产的PVA降解酶的降解性质及其酶催化反应动力学进行了研究。通过测定在PVA降解过程中酶活的变化,采用＂先假设-后验证＂的方法研究酶催化动力学方程。结果表明,在PVA未完全降解时,该降解酶的酶活随着PVA降解效率的提高而降低;在完全降解后,其酶活趋于一定。随着PVA浓度的升高,酶活逐渐提高。该酶的米氏常数Km=2.06×10^-3mol/L,最大反应速率Vmax=19.5U/min,得到该酶对PVA的催化反应动力学方程,为V=19.5[S]/（2.06×10^-3＋[S]）,从而为混合菌系的实际应用提供理论依据。