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菠萝叶片PEP羧激酶活性及草酰乙酸与腺苷酸库的昼夜变化

林桂芳, 彭长连, 林植珠, 李双顺

中科院华南植物研究所. 广东, 广州(510650)

摘要

自然条件下生长的菠萝植株,其叶片的PEP羧激酶的脱羧与可逆羧化活性于中午12时最大值。脱羧/羧化比值在上午明显高于下午和晚上。脱羧反应产物OAA含量于夜间增高, 至次日早晨6时最高, 随后下降。白天的OAA/Mal值高于夜间。参与Mal及OAA形成转化的PEPC和MDH活性 的昼夜变化与PEP羧激酶活性的图式相似。PEP羧激酶脱羧反应的另一底物ATP在夜间0-6时内处于低水平, 白天9-15时内则显著增高。图7参19

关键词： PEP羧激酶; 草酰乙酸; 腺苷酸; 昼夜变化; 菠萝

Diurnal changes of phosphoenolpyruvate carboxykinase activity, oxalacetate content and adenosine pool in pineapple leaves

Lin Guifang, Peng Changlian, Lin Zhizhu, Li Shuangshun

South China Institute of Botany, The Chinese Academy of Sciences. Guangzhou, Guangdong

Abstract

The day/night cycles of decarboxylation and carboxylation of phosphoenolpyruvate carboxykinase (PEPCK)and the levels of its substrate oxalacetate, ATP and ADP from greenhouse-grown pineapple leaves were studied. The diurnal change in both forward and reverse activities of PEPCK showed a two-peak pattern with a maximum at noon(12h)and another smaller one at midnight (21h). The average decarboxylation/carboxylation ratio in the morning was higher than those in the afternoon and night time. The contents of malate and oxalacetate increased at night and reached their maxima in the morning (6h~9h)and then declined. OAA/malate ratio was higher in day time than atnight. The day/night cycles of the activities of PEP carboxylase and malate dehydrogenase were coincident with that of PEPCK activity. ATP and ADP contents increased progressively from 9h to 15h and then decreased. It was almost undetectable through 24h to 6h. The ratio of ATP/ADP showed pronounced diurnal fluctuation. The results suggested that the substrate level was the important factor regulating PEPCK activity and its catalytic direction, and the activity of PEPCK was related with the activties of PEP carboxylase and ......

Key words: PEP carboxykinase;Oxalacetute;ATP;ADP;Pineapple

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引用本文：

林桂芳, 彭长连, 林植珠, 李双顺. 菠萝叶片PEP羧激酶活性及草酰乙酸与腺苷酸库的昼夜变化[J]. 生理学报 1994; 46 (4): .

Lin Guifang, Peng Changlian, Lin Zhizhu, Li Shuangshun. Diurnal changes of phosphoenolpyruvate carboxykinase activity, oxalacetate content and adenosine pool in pineapple leaves. Acta Physiol Sin 1994; 46 (4): (in Chinese with English abstract).