Tornheim K, Andrés V, Schultz V
Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118.
J Biol Chem. 1991 Aug 25;266(24):15675-8.
Oscillatory behavior of glycolysis in cell-free extracts of skeletal muscle involves repeated bursts of phosphofructokinase activity and associated oscillations in the [ATP]/[ADP] ratio. Addition of citrate, a potent physiological inhibitor of phosphofructokinase, decreased the frequency of the oscillations and delayed the first burst of phosphofructokinase activity in a dose-dependent manner. Citrate decreased the trigger point [ATP]/[ADP] ratio at which bursts of phosphofructokinase activity were initiated but had a much smaller effect on the average [ATP]/[ADP] ratio and did not decrease the peak values of the ratio. When oscillations were prevented by addition of fructose-2,6-P2, the decrease in the [ATP]/[ADP] ratio caused by citrate in the steady state system was similar to the decrease in the trigger point [ATP]/[ADP] ratio in the oscillatory system. The decrease in the average [ATP]/[ADP] ratio was greater in the steady state system than in the oscillating system. These results demonstrate advantages of oscillatory behavior of glycolysis in the regulation of carbohydrate utilization and the maintenance of a high [ATP]/[ADP] ratio.
骨骼肌无细胞提取物中糖酵解的振荡行为涉及磷酸果糖激酶活性的反复爆发以及[ATP]/[ADP]比值的相关振荡。添加柠檬酸（一种有效的磷酸果糖激酶生理抑制剂）会降低振荡频率，并以剂量依赖的方式延迟磷酸果糖激酶活性的首次爆发。柠檬酸降低了引发磷酸果糖激酶活性爆发的触发点[ATP]/[ADP]比值，但对平均[ATP]/[ADP]比值的影响要小得多，并且不会降低该比值的峰值。当通过添加果糖-2,6-二磷酸来阻止振荡时，柠檬酸在稳态系统中引起的[ATP]/[ADP]比值下降与振荡系统中触发点[ATP]/[ADP]比值的下降相似。稳态系统中平均[ATP]/[ADP]比值的下降比振荡系统中的更大。这些结果证明了糖酵解振荡行为在调节碳水化合物利用和维持高[ATP]/[ADP]比值方面的优势。
