Sanwal G G, Greenberg E, Hardie J, Cameron E C, Preiss J
Plant Physiol. 1968 Mar;43(3):417-27. doi: 10.1104/pp.43.3.417.
The ADPglucose pyrophosphorylases of 7 plant-leaf tissues were partially purified and characterized. In all cases the enzymes showed stability to heat treatment at 65 degrees for 5 minutes in the presence of 0.02 m phosphate buffer, pH 7.0. The leaf ADPglucose pyrophosphorylases were activated 5 to 15-fold by 3-phosphoglycerate. Fructose-6-phosphate and fructose 1, 6-diphosphate stimulated ADPglucose pyrophosphorylase to lesser extents. The A(0.5) (conc of activator required to give 50% of the observed maximal activation) of 3-phosphoglycerate for the barley enzyme was 7 x 10(-6)m while for the sorghum enzyme it was 3.7 x 10(-4)m. Inorganic phosphate proved to be an effective inhibitor of ADPglucose synthesis. The I(0.5) (conc of inhibitor that gave 50% inhibition of activity for the various leaf enzymes varied from 2 x 10(-5)m (barley) to 1.9 x 10(-4)m (sorghum). This inhibition was reversed or antagonized by the activator 3-phosphoglycerate. These results form the basis for an hypothesis of the regulation of leaf starch biosynthesis.
对7种植物叶片组织的ADP葡萄糖焦磷酸化酶进行了部分纯化和特性鉴定。在所有情况下,这些酶在含有0.02 m磷酸盐缓冲液(pH 7.0)的条件下,于65摄氏度热处理5分钟后仍表现出稳定性。叶片中的ADP葡萄糖焦磷酸化酶被3-磷酸甘油酸激活了5至15倍。6-磷酸果糖和1,6-二磷酸果糖对ADP葡萄糖焦磷酸化酶的刺激程度较小。大麦酶的3-磷酸甘油酸的A(0.5)(产生50%观察到的最大激活所需的激活剂浓度)为7×10(-6)m,而高粱酶的为3.7×10(-4)m。无机磷酸盐被证明是ADP葡萄糖合成的有效抑制剂。I(0.5)(对各种叶片酶产生50%活性抑制的抑制剂浓度)从2×10(-5)m(大麦)到1.9×10(-4)m(高粱)不等。这种抑制作用可被激活剂3-磷酸甘油酸逆转或拮抗。这些结果构成了叶片淀粉生物合成调控假说的基础。