CHLOROPLAST PHOSPHOFRUCTOKINASE .2. PARTIAL-PURIFICATION, KINETIC AND REGULATORY PROPERTIES
CHLOROPLAST PHOSPHOFRUCTOKINASE .2. PARTIAL-PURIFICATION, KINETIC AND REGULATORY PROPERTIES
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DOI：
10.1104/pp.60.2.295
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发表时间：
1977-01-01
期刊：
影响因子：
7.4
通讯作者：
LATZKO, E
中科院分区：
文献类型：
--
作者：
KELLY, GJ;LATZKO, E
2.7.1.11菠菜（Spinacia oleracea L.）通过硫酸铵和丙酮的分级组合，然后在DEAE-Sephadex A-50上层析，纯化约40倍。该酶与底物果糖6-磷酸之间的相互作用具有正协同动力学。当果糖6-磷酸浓度低于0.5mM时，最适pH从7.7向7.0移动。第二底物是MgATP 2-（Km 30 μ M）。游离ATP抑制该酶。叶绿体磷酸果糖激酶是敏感的抑制低浓度的磷酸烯醇式丙酮酸和乙醇酸2-磷酸（特别是在较高的pH值），这些化合物抑制在一个积极的合作方式。还记录了2-磷酸甘油酸盐（可能还有3-磷酸甘油酸盐）、柠檬酸盐和Pi的抑制作用;然而，Pi有效地缓解了磷酸烯醇丙酮酸盐和乙醇酸2-磷酸盐的抑制作用。这些调节特性被认为是对ADP-葡萄糖焦磷酸化酶和果糖二磷酸酶在叶绿体淀粉代谢调节中的补充。
Chloroplast phosphofructokinase [EC 2.7.1.11] from spinach (Spinacia oleracea L.) was purified approximately 40-fold by a combination of fractionations with ammonium sulfate and acetone followed by chromatography on DEAE-Sephadex A-50. Positive cooperative kinetics was observed for the interaction between the enzyme and the substrate fructose 6-phosphate. The optimum pH shifted from 7.7 toward 7.0 as the fructose 6-phosphate concentration was taken below 0.5 mM. The 2nd substrate was MgATP2- (Km 30 .mu.M). Free ATP inhibited the enzyme. Chloroplast phosphofructokinase was sensitive to inhibition by low concentrations of phosphoenolpyruvate and glycolate 2-phosphate (especially at higher pH); these compounds inhibited in a positively cooperative fashion. Inhibitions by glycerate 2-phosphate (and probably glycerate 3-phosphate), citrate, and Pi were also recorded; however, Pi effectively relieved the inhibitions by phosphoenolpyruvate and glycolate 2-phosphate. These regulation properties are considered to complement those of ADP-glucose pyrophosphorylase and fructosebisphosphatase in the regulation of chloroplast starch metabolism.