Connett R J
Department of Physiology, School of Medicine and Dentistry, University of Rochester, New York 14642.
J Appl Physiol (1985). 1987 Dec;63(6):2366-74. doi: 10.1152/jappl.1987.63.6.2366.
Glycogen phosphorylase activity and several glycolytic intermediates were measured at rest and after 5, 10, 15, 30, 60, and 180 s of twitch stimulation at 4 Hz in fast-frozen samples of gracilis muscle. During an initial burst of glycolysis (0-5 s) only 3-phosphoglycerate and lactate accumulate. These changes are reversed during the period of low glycolytic flux (5-30 s). During a second burst of glycolysis (30-60 s) most glycolytic intermediates increase. The levels of glycogen phosphorylase a changes in parallel with the initial burst of glycolysis but remain at resting levels throughout the second burst. The phosphoglycerate mutase-enolase steps deviate from equilibrium during the initial burst of glycolysis, suggesting a transiently rate-limiting role. Analysis using a model of phosphofructokinase kinetics indicates that combined changes in cytosolic pH (R. J. Connett, J. Appl. Physiol. 63: 2360-2365, 1987) and free [ADP] and [AMP] can account for the initial burst of glycolysis. The second burst of glycolysis requires other regulatory factors. It is concluded that an initial alkalization is a major regulatory factor in the early burst of glycolysis during a rest-to-work transition in red muscle.
在股薄肌快速冷冻样本中，于静息状态以及在4Hz频率下进行5、10、15、30、60和180秒的抽搐刺激后，测量糖原磷酸化酶活性和几种糖酵解中间产物。在糖酵解的初始爆发阶段（0 - 5秒），仅3 - 磷酸甘油酸和乳酸积累。这些变化在糖酵解通量较低的阶段（5 - 30秒）会逆转。在糖酵解的第二次爆发阶段（30 - 60秒），大多数糖酵解中间产物增加。糖原磷酸化酶a的水平与糖酵解的初始爆发阶段平行变化，但在第二次爆发阶段全程保持在静息水平。在糖酵解的初始爆发阶段，磷酸甘油酸变位酶 - 烯醇化酶步骤偏离平衡，提示其具有瞬时限速作用。使用磷酸果糖激酶动力学模型进行分析表明，胞质pH（R. J. Connett，《应用生理学杂志》63: 2360 - 2365，1987）、游离[ADP]和[AMP]的综合变化可以解释糖酵解的初始爆发。糖酵解的第二次爆发需要其他调节因子。结论是，初始碱化是红色肌肉从静息到工作转变过程中糖酵解早期爆发的主要调节因子。
