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小麦叶绿体中细胞分裂素结合蛋白的特性

张华敏, 刘愚, 沈允钢

中科院上海植物生理研究所.上海 200032

摘要

小麦叶绿体中的CTK结合蛋白属热敏感蛋白,它与6-BA结合的最适温度约为25℃;最适pH为8左右;在其蛋白分子上存在两类CTK结合位点,高亲和力位点与6-BA结合的Ka值为1.1×10~(-9)mol/L,低亲和力位点的Ka值为9×10~(-7)mol/L;激动素、玉米素对6-BA的结合只有部分抑制作用,而ABA、GA3、IAA及腺嘌呤则无竞争作用。CTK结合蛋白分子中的中性氨基酸含量很高,在中性介质中带弱负电。

关键词： 小麦叶绿体; CTK; CTK结合蛋白

Properties of a CTK-binding protein from wheat chloroplasts

Zhang Huamin, Liu Yu, Shen Yungang

Shanghai Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghai 200032

Abstract

A CTK-binding protein from wheat chloroplasts was shown to be heat-labile . It showed high binding activity to 6-BA by sedimentation method at 25℃ and pH 7-8. Scatchard plot showed two classes of binding sites in this CTK-binding protein, with Kα values of 1.1×10~(-9)mol/L and 9×10~(-7) mol/L. showed that the binding of 6-BA to this protein was partially inhibited by kinetin and zeatin, but not inhibited by ABA, GA, IAA and adenine. The amino acid composition of the CTK-binding protein indicated that it is rich in neutral amino acids and to have negative charge in a neutral medium.

Key words: Wheat chloroplast;CTK;CTK binding protein

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引用本文：

张华敏, 刘愚, 沈允钢. 小麦叶绿体中细胞分裂素结合蛋白的特性[J]. 生理学报 1996; 48 (1): .

Zhang Huamin, Liu Yu, Shen Yungang. Properties of a CTK-binding protein from wheat chloroplasts. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).