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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

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Citing This Article：

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).