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Ca~(2+)/CaM介导生长素对小麦胚芽鞘细胞NAD激酶的刺激作用

李霞, 王宁宁, 王淑芳, 朱亮基

南开大学生物化学与分子生物学系.天津 300071

摘要

外源IAA处理可以显著增加小麦胚芽鞘细胞NAD激酶的催化活性,钙离子可以增强IAA的作用效果,而钙离子通道抑制剂LaCl_(3)则起强烈的抑制作用,但在存在钙离子的条件下,这种抑制作用可以被钙离子载体A23187消除;钙调蛋白能够在离体条件下激活经过DEAE纤维素柱纯化的小麦胚芽鞘NAD激酶,经过IAA处理的胚芽鞘细胞中能够刺激NAD激酶活性的钙调蛋白含量明显增加,IAA的这一作用受LaCl_(3)的抑制

关键词： 小麦胚芽鞘; NAD激酶; 钙离子; 钙调蛋白

The effect of IAA and NAD kinase in wheat coleoptile is mediated by Ca~(2+)/calmodulin complex

Li Xia, Wang Ningning, Wang Shufang, Zhu Liangji

Biochemistry and Molecular Biology Department of Nankai University.Tianjin 300071

Abstract

NAD kinase (NADK) catalyzes the only known biochemical reaction leading to the phosphorylation of NAD~(+) to form NADP~(+), which is a rate-limiting factor in many reactions in plants and plays a key role in the control of metabolism. Enhanced by calcium, exogenous IAA increased NADK activity in etiolated wheat coleoptile segments. LaCl_(3), a potent calcium ion channel blocker, could inhibit effectively the IAA-induced activity of NADK. The inhibitive effect of LaCl_(3) could be reversed by the calcium ionophore A23187. Calmodulin could activate in vitro the NADK purified by anion exchange chromatography from wheat coleoptile segments. LaCl_(3), however, almost completely abolished the IAA-induced increase in NADK-dependent calmodulin content in wheat coleoptile.

Key words: Wheat coleoptile;NAD kinase;Ca~(2+);Calmodulin

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引用本文：

李霞, 王宁宁, 王淑芳, 朱亮基. Ca~(2+)/CaM介导生长素对小麦胚芽鞘细胞NAD激酶的刺激作用[J]. 生理学报 1999; 51 (4): .

Li Xia, Wang Ningning, Wang Shufang, Zhu Liangji. The effect of IAA and NAD kinase in wheat coleoptile is mediated by Ca~(2+)/calmodulin complex. Acta Physiol Sin 1999; 51 (4): (in Chinese with English abstract).