| Kinetics of Inhibition of Polyphenol Oxidase Obtained from Tobacco Nicotiana Tobacum |
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| 作者姓名： | 刘卫群 饶学明 潘继承 周海梦 |
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| 作者单位： | [1]CollegeofAgronomy,HenanAgriculturalUniversity,Zhengzhou450002,China [2]DepartmentofBiologicalSciencesandBiotechnology,TsinghuaUniversity,Beijing100084,China |
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| 基金项目： | the National Key Basic Research and Develop-ment (973) Program of China (No. G1999075607) and the Henan Natural Science Foundation (No. G0111010700) |
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| 摘 要： | In this study, the kinetics of inhibition of polyphenol oxidase by L-cysteine has been investigated. The inhibition of tobacco polyphenol oxidase was studied using the progress-of-substrate-reaction method proposed by Tsou, following the substrate reaction during irreversible inhibition of the enzyme activity. Analysis of the inhibition kinetics shows that inhibition occurs by an irreversible and non-complexation reaction. The microscopic rate constants were determined for reaction of the inhibitor both with the free enzyme and with the enzyme-substrate complex. The results show that the presence of the substrate has a significant protective effect of the enzyme against inactivation by L-cysteine.
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| 关 键 词： | 动力学 多酚氧化酶 烟草 L-半胱氨酸 PPOs |
Kinetics of Inhibition of Polyphenol Oxidase Obtained from Tobacco Nicotiana Tobacum |
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| LIU Weiqun ,RAO Xueming,PAN Jicheng ?ZHOU Haimeng College of Agronomy,Henan Agricultural University,Zhengzhou ,China.Kinetics of Inhibition of Polyphenol Oxidase Obtained from Tobacco Nicotiana Tobacum[J].Tsinghua Science and Technology,2004,9(1):94-97. |
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| Authors: | LIU Weiqun RAO Xueming PAN Jicheng ?ZHOU Haimeng College of Agronomy Henan Agricultural University Zhengzhou China |
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| Abstract: | In this study, the kinetics of inhibition of polyphenol oxidase by L-cysteine has been investigated. The inhibition of tobacco polyphenol oxidase was studied using the progress-of-substrate-reaction method proposed by Tsou, following the substrate reaction during irreversible inhibition of the enzyme activity. Analysis of the inhibition kinetics shows that inhibition occurs by an irreversible and non-complexation reaction. The microscopic rate constants were determined for reaction of the inhibitor both with the free enzyme and with the enzyme-substrate complex. The results show that the presence of the substrate has a significant protective effect of the enzyme against inactivation by L-cysteine. |
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| Keywords: | tobacco polyphenol oxidase kinetics irreversible inhibition |
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