Acta Chimica Sinica ›› 2001, Vol. 59 ›› Issue (4): 492-495. Previous Articles     Next Articles

Original Articles

微量热法研究过氧化氢酶底物抑制动力学

王志勇;刘欲文;汪存信;张绍辉;屈松生   

  1. 武汉大学化学与环境科学学院
  • 出版日期:2001-04-15 发布日期:2001-04-15

Microcalorimetric studies on the substrate- inhibitory kinetics of catalase

Wang Zhiyong;Liu Yuwen;Wang Cunxin;Zhang Shaohui;Qu Songsheng   

  • Online:2001-04-15 Published:2001-04-15

Catalase is an important enzyme of biological defense against oxygen toxicity. It has been detected in a wide range of aerobe. The decomposition of hydrogen peroxide catalyzed by catalase is a bi- substrate enzyme-catalyzed reaction. As Chance proposed, it is an overall first-order reaction. The decomposition of hydrogen peroxide (H2O2) catalyzed by catalase is incomplete under high substrate concentration. It is because that there exists irreversible substrate inhibition of catalase. We proposed a possible irreversible substrate-inhibitory mechanism. Using this mechanism, we studied the kinetics of catalse while the reaction was incomplete. The result is satisfactory. At 310.15K and pH=7.0, k0 and k1/k2 are calculated and to be 9.6×10^5L·mol^-1·s^-1 and 2.9×10^6, respectively.

Key words: CATALASE, THERMODYNAMICS, CALORIMETRY

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