J Integr Plant Biol. ›› 2001, Vol. 43 ›› Issue (11): 1140-1145.

• Research Articles • Previous Articles     Next Articles

Effect of Lysophosphatidylcholine on ATP and ρ-Nitrophenyl Phosphate Hydrolysis by the Plasma Membrane H+-ATPase from Soybean Hypocotyls

QIU Quan-Sheng, ZHANG Nan   


The stimulatory effect of lysophosphatidylcholine (lyso-PC) on ATP and ρ-nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H+-ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Results showed that lyso-PC stimulated the hydrolysis of ATP; ATP hydrolysis was enhanced dramatically when lyso-PC was within 0-0.03%, and increased slightly when lyso-PC was higher than 0.03%. At the concentration of 0.03%, lyso-PC stimulated ATP hydrolysis by 80.5%. Kinetics analysis showed that V max increased from 0.46μmol Pi·mg-1 protein·min-1 to 0.87 μmol Pi·mg-1 protein·min-1 while Km increased from 0.88 mmol/L to 1.15 mmol/L under lyso-PC treatment. The optimum pH of ATP hydrolysis was shifted from 6.5 to 7.0. Moreover, it was found lyso-PC enhanced the inhibition of ATP hydrolysis by hydroxylamine. In the presence of 200 mmol/L hydroxylamine, ATP hydrolysis was inhibited by 74.4%, while it was inhibited by 84.4% when treated with lyso-PC. However, PNPP hydrolysis and the inhibitory effect of vanadate were not affected by lyso-PC. The above results indicated that the kinase domain might be an action site or regulatory region of the C-terminal autoinhibitory domain in the plant plasma membrane H+-ATPase.

溶血卵磷脂对大豆下胚轴质膜H+-ATPase ATP 和对-硝基苯磷酸水解活性的影响
邱全胜*  张楠

摘要:研究了溶血卵磷脂(lysophosphatidylcholine, lyso-PC)对大豆(Glycine max (L.) Merr.)下胚轴质膜H+-ATPase ATP 和对-硝基苯磷酸(ρ-nitrophenyl phosphate, PNPP )水解的影响.结果显示,lyso-PC 可以刺激ATP水解活力,当lyso-PC 浓度在0~0.03%范围时,ATP水解活力明显提高,lyso-PC浓度高于0.03%后增加缓慢;当lyso-PC浓度为0.03%时, ATP水解活力提高80.5%.动力学分析表明,lyso-PC处理可以使ATP水解的Vmax 从0.46 μmol Pi·mg-1 protein·min-1升高到 0.87 μmol Pi·mg -1 protein·min-1;使Km从0.88 mmol/L升高到1.15 mmol/L. 最适pH 也从6.5变为7.0.实验还发现lyso-PC可以促进羟胺对ATP水解的抑制作用,lyso-PC处理后ATP 水解被羟胺(200 mmol/L)抑制84.4%,而未经lyso-PC处理的对照组则仅被抑制74.4%.然而,l yso- PC处理不影响PNPP水解活力和钒酸钠抑制效应.以上结果表明,质膜H+-ATPase 的激酶结构域可能是其C末端自抑制结构域的作用位点或调节区域.
关键词: 溶血卵磷脂;大豆;下胚轴;质膜:; H+-ATPase ;C 末端自抑制结构域;激酶结构域

Key words: lysophosphatidylcholine (lyso-PC), soybean hypocotyls, plasma membrane H+-ATPase, C-terminal autoinhibitory domain, kinase domain

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