过刊浏览

水稻RubisCO的纯化及其与烟草RubisCO性质的比较

缪有刚, 李立人

中国科学院上海植物生理研究所

摘要

利用蔗糖密度梯度离心和DEAE-Sepharose fast flow柱层析等步骤从水稻叶 片中纯化了RubisCo。此法快速, 酶的收得率高, 酶的比活达1.15μmol CO2min ~(-1) mg~(-1)。水稻RubisCO的热稳定性比烟草酶差, 在活化时对Mg~ (+)较敏感。水稻和烟草RubisCO钝化态时总巯基数和表面巯基数相同, 当酶活 化后, 水稻酶表面巯基数增加, 烟草酶减少。当这些表面巯基被修饰后, 水稻酶 活性损失60%, 烟草酶活力仅损失15%。水稻和烟草RubisCO的远紫外CD光谱有明 显的区别, 显示了两者在二级结构、酶比活和性质上的重大差别。

关键词： 水稻; 纯化; 烟草; RubisCO

Purification of RubisCO from rice and its properties compared with those of tobacco

Miao Yougang, Li Liren

Shanghai Inst. Plant Physiol., Acad. Sin.

Abstract

The eluted samples were layered on a linear gradient of 25% to 40% (w/v) sucrose and centrifuged at 240000xg for 2.5 hours. The active fractions were pooled and applied to a column of DEAT-Sepharose fast flow, and eluted with the same buffer containing a linear gradient of 0 to 0.5 mmol/L NaCl. The specific activityof the purified enzyme was about 1.15 MUmol CO sub(2) mg super(-1) protein min super(-1). It was found that rice RubisCO was more labile to heat than the tobacco enzyme. Addition of Mg super(2+) had no effect on the tobacco enzyme. The total SH groups and the surface SH groups for rice and tobacco enzymes were the same However, the surface SH groups of the two enzymes after heat reactivation showed a significant difference. When all surface SH groups were modified by DTNB, the rice enzyme lost 60% of its activity, but the tobacco enzyme lost only 15%. These results indicate that the difference in properties between rice and tobacco enzymes were probably caused by the differences in their structure.

Key words: RubisCO;Rice;Tobacco;Purification

收稿日期：　　录用日期：

通讯作者：　　E-mail:

引用本文：

缪有刚, 李立人. 水稻RubisCO的纯化及其与烟草RubisCO性质的比较[J]. 生理学报 1991; 43 (2): .

Miao Yougang, Li Liren. Purification of RubisCO from rice and its properties compared with those of tobacco. Acta Physiol Sin 1991; 43 (2): (in Chinese with English abstract).