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菠菜叶片蔗糖磷酸合成酶的调节

吴勇, 於新建, 苏丽英, 夏叔芳

中国科学院上海植物生理研究所

摘要

电泳均一的菠菜叶片蔗糖磷酸合成酶的活力受G6P、Mg~(2+)、Mn ~(2+) 的调节; G6P 对此酶的促进作用在F6P浓度较低时表现得比较明显; 此酶对Mn上 标(2+)较对Mg~(2+)敏 感, Mg~(2+)、Mn~(2+)对此酶的促进作用可被EDTA 解除。底物F6P的饱和曲线为S型, 底物UDPG的饱和曲线为双曲线型。NADP是此酶 的负效应剂, NADP对F6P表现为混合型抑制, 使Vm(F6P)降低和Km(F6P)增大, 3mmol/L NADP使F6P的κm值从2.5mmol/L上升至3.8mmol/L, 但不影响希尔系数, n=1.3。NADP 对UDPG表现为κm不变的非竞争性抑制, κm(UDPG)=3.8mmL。图5参11

关键词： 菠菜; 叶片; SPS

Regulation of spinach leaf sucrose phosphate synthetase

Wu Yong, Yu Xinjian, Su Liying, Xia Shufang

Shanghai Inst. Plant Physiol., Acad. Sin.

Abstract

Polyacrylamide gel electrophoresis confirmed that at subsaturation concentration of F6P, G6P had a stimulatoy effect on sucrose phosphate synthetase. Both mg super(2+) and Mn super(2+) activated sucrose phosphate synthetase, while EDTA antagonized this activation. We found that NADP inhibited the activity of sucrose phosphate synthetase. The saturation curve of F6P was shown in Fig. 4A. In the presence of NADP, V sub(m) (F6P) decreased and K sub(m) (F6P) increased from 2.5 to 3.8 mmol/L (Fig. 4B), but the Hill coefficient remained unchanged (n=1.3) (Fig. 4A). The saturation curve of UDPG was hyperbolic in shape (Fig. 5A). Inhibition of NADP was noncompetitive with UDPG (Fig. 5B). Concentration of UDPG for 50% maximal activity was 3.8 mmol/L.

Key words: Spinach leaves;Sucrose phosphate synthetase;G6P

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引用本文：

吴勇, 於新建, 苏丽英, 夏叔芳. 菠菜叶片蔗糖磷酸合成酶的调节[J]. 生理学报 1991; 43 (2): .

Wu Yong, Yu Xinjian, Su Liying, Xia Shufang. Regulation of spinach leaf sucrose phosphate synthetase. Acta Physiol Sin 1991; 43 (2): (in Chinese with English abstract).