双酶协同水解微波改性木薯淀粉的动力学研究

Study of Synergism Kinetics of α-Amylase and Glucoamylase on Hydrolysis of Microwave Modified Tapioca Starch

研究了α 淀粉酶和葡萄糖苷酶协同水解微波改性木薯淀粉的动力学,在单一水解体系中,α 淀粉酶和葡萄糖苷酶对微波改性淀粉颗粒的降解遵循Michaelis Menten方程,葡萄糖苷酶的米氏常数Km=18 718mol/mL,最大反应初速度Vmax=0 745mol/(mL·min),α 淀粉酶的米氏常数Km=88 334mol/mL,最大反应初速度Vmax=1 039mol/(mL·min)。葡萄糖对反应体系具有竞争性抑制剂的作用,其抑制常数Ki=9 656×10-4mol/mL。双酶协同作用的水解效率比单酶作用的水解效率高。

The formation of glucose in sole α-amylase or glucoamylase system obeys the Michaelis-Menten mechanism.The Michaelis constant of glucoamylase K_m is 18.718 mol/mL,and maximum velocity is 0.745 mol/(mL·min).The Michaelis constant of α-amylase K_m is 88.334 mol/mL,and maximum velocity is 1.039 mol/(mL·min).The reaction rate decreases gradually because of competitive inhibition of glucose.The soluble sugar formation by the mixed enzyme system is more than twice as much as that by any single enzyme system due to synergistic cooperation of both enzymes.