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O_(1)、ACC和CO_(2)对番木瓜ACC氧化酶活性的影响

宋松泉, Yip Wing-Kin

中山大学基因工程教育部重点实验室与生命科学学院.广东,广州 510275；Department of Botany,University of Hong Kong. Pokfulam Road, Hong Kong

摘要

通过DEAE-Sepharose和Phenyl-Sepharose柱层析后,番木瓜果皮ACC氧化酶被纯化了19.5倍。在乙烯产生中,ACC氧化酶对O_(2)的K_(m)值主要取决于ACC的浓度,随着ACC水平的增加而下降;当O_(2)的浓度增加时,酶对ACC的K_(m)值降低。CO_(2)显著地增加酶的活性以及对O_(2)和ACC的K_(m)值。Fe~(2+)提高酶的活性,Co~(2+)抑制酶的活性;Fe~(2+)能够拮抗Co~(2+)对酶活性的抑制作用。这些动力学资料表明ACC氧化酶遵循一种顺序结合机制,首先与O_(2)结合,然后与ACC结合。

关键词： ACC氧化酶; 番木瓜; CO2; Fe2+; 抑制剂; Km值; 部分纯化

Effect of O_(2), ACC and CO_(2) concentration on the activity of partially purified ACC oxidase from papaya

Song Songquan, Yip Wing-Kin

The Key Laboratory of Gene Engineering of Ministry of Education,School of Life Sciences,Zhongshan University.Guangzhou 510275,Guangdong

Abstract

ACC oxidase has been purified 19.5-fold by using DEAE-Sepharose and Phenyl-Sepharose columns. The K_(m) value by ACC oxidase for O_(2) in ethylene production varied greatly depending on the ACC concentration, and decreased with increase of ACC levels. The K_(m) value for ACC also declined as oxygen concentration increased. The enzyme activity was dramatically increased by CO_(2), and the K_(m) value for O_(2) and for ACC increased with increase of CO_(2) concentration. Enzyme activities were obviously increased by Fe~(2+) and significantly inhibited by Co~(2+); and Fe~(2+) could antagonize the inhibotory role of Co~(2+). These kinetic data are consistent with the view that the catalytic role of ACC oxidase follows an ordered binding mechanism in which ACC oxidase binds first to O_(2) and then to ACC.

Key words: ACC oxidase;Carica papaya L.;CO_(2);Fe~(2+);Inhibitor;Kn;Value

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引用本文：

宋松泉, Yip Wing-Kin. O_(1)、ACC和CO_(2)对番木瓜ACC氧化酶活性的影响[J]. 生理学报 2001; 53 (5): .

Song Songquan, Yip Wing-Kin. Effect of O_(2), ACC and CO_(2) concentration on the activity of partially purified ACC oxidase from papaya. Acta Physiol Sin 2001; 53 (5): (in Chinese with English abstract).