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一组玉米胚钙沉淀蛋白的初步研究

龚明, 李忠光, 杜朝昆, 高良

云南师范大学生命科学系.云南,昆明 650092

摘要

从玉米胚中分离出一组理化性质相似的可为钙所沉淀的蛋白。该组蛋白可被3%的三氯乙酸和55%的硫酸铵可逆沉淀,具有较高的热稳定性,在93-94℃下5min不沉淀。该组钙沉淀蛋白可被等于或大于1mmol/L的CaCl_(2)可逆地沉淀,但不被MgCl_(2)或NaCl沉淀。该组蛋白在EGTA存在下可与phenyl-sepharose 4B结合而被含Ca~(2+)的缓冲液所洗脱。它们由7种蛋白质组成,亚基分子量为16-103kD。它们的一些理化性质类似于从动物肌肉细胞中提取的钙结合蛋calsequestrin,其功能可能与缓冲和调节细胞游离Ca~(2+)水平有关。

关键词： 钙; 钙沉淀蛋白; 钙结合蛋白; 玉米; 胚

The preliminary characterization of a group of calcium-precipitable protein s from maize germ

Gong Ming, Li Zhongguang, Du Chaokun, Gao Liang

Department of Life Sciences,Yunnan Normal University.Kunming 650092,Yunan

Abstract

This paper reports a group of calcium-precipitable proteins (CaPPs) isolated from maize germ for the first time by a procedure involving reversible precipitation by 3% trichloroacetic acid and 55% (NH_(4))_(2)SO_(4), heat denaturation and Ca~(2+)-induced reversible precipitation. This group of CaPPs showed higher heat stability, and kept undenaturated at 93-94 degree C for 5 min. In addition, they could be reversibly precipitated when the Ca~(2+) concentration of the solution was equal to or higher than 1 mmol/L, bind hydrophobically to phenyl-sepharose 4B in the absence of Ca~(2+) and were dissociated from phenyl-sepharose column in a Ca~(2+)-dependent manner. Electrophoretic analysis showed that this group of CaPPs consists of 7 proteins, the molecular weights of which subunits range from 16 to 103 kD. This group of CaPPs showed some of the properties similar to calsequestrin isolated from muscle cells, suggesting that they might be involved in the regulation of intracellular Ca~(2+) level through its buffering action.

Key words: Calcium;Calcium-precipitable proteins;Calcium-binding proteins;Maize;Germ

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引用本文：

龚明, 李忠光, 杜朝昆, 高良. 一组玉米胚钙沉淀蛋白的初步研究[J]. 生理学报 1997; 49 (3): .

Gong Ming, Li Zhongguang, Du Chaokun, Gao Liang. The preliminary characterization of a group of calcium-precipitable protein s from maize germ. Acta Physiol Sin 1997; 49 (3): (in Chinese with English abstract).