过刊浏览

水稻叶片在自然衰老过程中1,5-二磷酸核酮糖羧化酶/加氧酶的降解

彭新湘, 彭少兵

华南农业大学生物技术学院.广东,广州 510642；国际水稻研究所.马尼拉

摘要

Rubisco在降解过程中其比活基本保持恒定,意味着未发生酶的失活,也就是说酶结构未发生根本性改变,由此也可初步判断酶未发生亚基间的交联聚合(已证明亚基交联可导致酶失活)。接着用SDS-PAGE和蛋白印迹技术证实了上述观点:Rubisco降解之前只有极少量的大亚基聚合体,随后同未聚合大亚基一起很快降解。此外,研究结果进一步表明酶分子在降解之前有少量与叶绿体膜结合,但降解过程中并未见膜结合蛋白增加。

关键词： 1,5-二磷酸核酮糖羧化酶/加氧酶; 降解; 自然衰老; 水稻

Degradation of ribulose-1, 5-bisphosphate carboxylase/oxygenase in naturally senescing rice leaves

Peng Xinxiang, Peng Shaobing

Lab of Molecular Plant Physiology,College of Biotechnology,South China Agricultural University.Guangzhou 510642,Guangdong

Abstract

During natural senescence of rice leaves, Rubisco and other soluble proteins were degraded at similar rates, starting from the 5th day after full expansion of the leaf, but the specific activity, expressed as #mu#mol CO_(2) per milligram Rubisco per minute, remained almost constant throughout the senescence period, meaning that inactivation of the enzyme did not occur during the process. Only a small portion of Rubisco large subunits (LSUs) was found to be aggregated (about 5% of total) before its breakdown and the aggregated LSUs were degraded as rapidly as the non-aggregated ones. The membrane-associated Rubisco LSUs did not increase during senescence, but were lost rapidly like the stroma ones.

Key words: Rubisco;Degradation;Naturally senescence;Rice

收稿日期：　　录用日期：

通讯作者：　　E-mail:

引用本文：

彭新湘, 彭少兵. 水稻叶片在自然衰老过程中1,5-二磷酸核酮糖羧化酶/加氧酶的降解[J]. 生理学报 2000; 52 (1): .

Peng Xinxiang, Peng Shaobing. Degradation of ribulose-1, 5-bisphosphate carboxylase/oxygenase in naturally senescing rice leaves. Acta Physiol Sin 2000; 52 (1): (in Chinese with English abstract).