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玉米根微粒体ABA结合蛋白的性质及逆境胁迫的影响

陈珈, 朱美君

北京农业大学生物学院.北京 100094

摘要

以玉米根微粒体为材料进行的微量放射配体结合(MRLB)实验表明玉米根微粒体膜上存在着ABA结合位点,ABA与ABA结合蛋白(ABA-BP)结合的最适pH为6.5,结合反应对温度(0℃和25℃)不太敏感,ABA与ABA-BP的结合反应是一个动态平衡过程,5min即可达最大结合(B_(max))的50%,30min达到最大结合,1 h内基本保持不变。胰蛋白酶处理表明此结合位点为蛋白质,冻融实验则表明此蛋白与ABA的结合不仅要求其自身具有特定构象而且需要有一定的膜脂环境,DTT处理实验结果显示ABA-BP中可能存在着二硫键。逆境处理可以提高玉米根微粒体膜对ABA的结合活性,盐胁迫、渗透胁迫、干旱胁迫和热冲激处理分别使结合活性上升34.9%、17.8%、23.1%和13.3%。

关键词： 结合蛋白; ABA专一结合; 逆境胁迫; ABA; 微粒体

Characteristics of ABA binding protein in microsome of maize roots and effects of environment stresses on its activity

Chen Jia, Zhu Meijun

College of Biological Sciences, Beijing Agricultural University.Beijing 100094

Abstract

Microvolume radioactivity ligand binding assay indicated that there were ABA binding sites in microsomes from maize roots.The amount of ABA bound was maximal at pH 6.5 and the activity was insensitive to temperature difference between 0℃and 25℃.After 5 min the amount bound reached 50% of the maximum value, which was reached after 30 min, and remained unchanged for 60 min. Trypsin digestion experiment showed that the binding sites were on the protein. The freezingthawing experiment showed that the activity of ABA binding protein depended not only on its own characteristic structure but also on some special membrane lipid micro-environment. Specific binding activity can be reduced by the reducing agent dithioerythritol. The results suggest that a reducible group, possibly a disulfide group, may be located at or near the binding site and are required for its action. The specific binding could be enhanced by stress treatment. Salt stress, osmotic stress, drought stress and heat shock treatment all increased specific binding activity, the extents of increase being 34.9, 17.8, 23.1 and 13.3% respectively.

Key words: Binding protein;ABA specific binding;Environment stress;ABA;Microsome

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引用本文：

陈珈, 朱美君. 玉米根微粒体ABA结合蛋白的性质及逆境胁迫的影响[J]. 生理学报 1996; 48 (1): .

Chen Jia, Zhu Meijun. Characteristics of ABA binding protein in microsome of maize roots and effects of environment stresses on its activity. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).