为了解超声波对微生物抗氧化酶类防御体系的影响机制,以过氧化氢酶（CAT）为对象,研究了不同超声波条件对CAT酶活的影响,同时采用红外光谱分析无超声作用和超声作用后CAT二级结构的变化。结果表明：CAT酶活随着超声波功率增大而降低,延长超声时间对CAT酶活影响不大;超声作用下CAT的稳定温度和pH值分别为37℃和7.4;经超声波处理后的CAT的动力学参数Km和Vmax值变大,且二级结构由有序向无序转变.

In order to reveal the influencing mechanism of ultrasonic on the antioxidation defense system of microorganisms,catalase（CAT） was treated with ultrasonic and the effects of ultrasonic parameters on the enzyme activity of CAT were studied.Moreover,the secondary structure of CAT with and without ultrasonic treatment were analyzed by means of FT-IR.The results show that（1） the enzyme activity of CAT decreases with the increase in ultrasonic power;（2）the prolonging of irradiation time has no obvious effect on the enzyme activity of CAT;（3） the stable temperature and pH value for CAT treated with ultrasonic are respectively 37℃ and 7.4;and（4） after ultrasonic treatment,the kinetic parameters Km and Vmax of CAT both increase,and the secondary structure transfers from an ordered structure to a disordered one.