Dietzler D N, Leckie M P, Magnani J L, Sughrue M J, Bergstein P E, Sternheim W L
J Biol Chem. 1979 Sep 10;254(17):8308-17.
When either fructose, glycerol, or succinate served as a sole source of carbon and energy in nitrogen-starved cultures of Escherichia coli W4597(K) the values of the kinetic constants of the equation that expresses the relationship between glycogen synthesis and hexose phosphates were different from the values observed when glucose was the sole source of carbon and energy. Addition of glucose during either exponential growth or nitrogen starvation to a culture using one of the other carbon sources slowed the rate of glycogen synthesis and shifted the values of the constants toward the values observed in cultures using glucose alone. Addition of cyclic AMP (cyclic adenosine 3':5'-monophosphate) during exponential growth of a culture using glucose caused the values of the constants to be shifted toward the values observed in cultures using a carbon source other than glucose. In all of the metabolic conditions studied in this report the adenylate energy charge ((ATP + 1/2 ADP)/(ATP + ADP + AMP)) and the level of the rate-limiting enzyme of glycogen synthesis, ADP-glucose synthetase (glucose 1-phosphate adenylyltransferase, EC 2.7.7.27), were the same. The data presented here indicate that the difference we observed in the quantitative relationship for glycogen synthesis is the result of the different cellular levels of cyclic AMP in the cells using glucose and the cells using one of the other carbon sources. Since cyclic AMP does not affect the velocity of ADP-glucose synthetase in vitro, apparently a change in the cellular level of cyclic AMP causes a shift in the cellular level of a presently unknown (and previously undetected) effector of this enzyme. The shift in the level of this effector evidently alters the response of the enzyme in vivo to the substrate glucose 1-phosphate and the activator fructose 1,6-diphosphate.
当在氮饥饿的大肠杆菌W4597(K)培养物中，果糖、甘油或琥珀酸作为唯一的碳源和能源时，表达糖原合成与己糖磷酸之间关系的方程的动力学常数的值，与以葡萄糖作为唯一碳源和能源时观察到的值不同。在指数生长或氮饥饿期间，向使用其他碳源之一的培养物中添加葡萄糖，会减缓糖原合成的速率，并使常数的值向仅使用葡萄糖的培养物中观察到的值转变。在使用葡萄糖的培养物指数生长期间添加环腺苷酸（环腺苷3':5'-单磷酸），会使常数的值向使用非葡萄糖碳源的培养物中观察到的值转变。在本报告研究的所有代谢条件下，腺苷酸能荷（(ATP + 1/2 ADP)/(ATP + ADP + AMP)）和糖原合成的限速酶ADP-葡萄糖合成酶（葡萄糖1-磷酸腺苷酰转移酶，EC 2.7.7.27）的水平是相同的。此处呈现的数据表明，我们在糖原合成定量关系中观察到的差异，是使用葡萄糖的细胞和使用其他碳源之一的细胞中环腺苷酸细胞水平不同的结果。由于环腺苷酸在体外不影响ADP-葡萄糖合成酶的活性，显然环腺苷酸细胞水平的变化会导致该酶目前未知（且先前未检测到）的效应物细胞水平的转变。这种效应物水平的转变显然改变了该酶在体内对底物葡萄糖1-磷酸和激活剂果糖1,6-二磷酸的反应。
