SELF-OSCILLATIONS IN GLYCOLYSIS .1. A SIMPLE KINETIC MODEL
SELF-OSCILLATIONS IN GLYCOLYSIS .1. A SIMPLE KINETIC MODEL
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DOI：
10.1111/j.1432-1033.1968.tb00175.x
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发表时间：
1968-01-01
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影响因子：
--
通讯作者：
SELKOV, EE
中科院分区：
文献类型：
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作者：
SELKOV, EE
本文提出了一个简单的具有底物抑制和产物活化的开放单底物酶反应动力学模型。该模型和磷酸果糖激酶反应之间的比较表明，它们的动力学性质之间的密切相似。这使得有可能定性地解释大多数关于糖酵解单频振荡的实验数据。对该模型的数学分析表明：在该模型中，在参数之间的确定关系，自振荡出现。低的源速率、大的产物汇速率常数、低的产物-酶亲和力和高的酶活性更容易满足自激条件。自振荡仅存在于决定底物抑制程度的参数的一定值范围内。该范围随着源速率的降低而增大。太强或相反，太弱的底物抑制导致阻尼振荡。自振荡的周期取决于底物抑制的程度、源速率、汇速率常数、酶活性、底物和产物对酶的亲和力;它随着这些值的增加而减小。随着相对下沉速率常数的增加，自振荡的稳态振幅最初增加，直到达到一个确定的最大值，然后下降到零。磷酸果糖激酶反应中的自振荡状态仅在该反应的最大速率基本上高于源速率并且低于控制产物汇的反应的最大速率时存在。磷酸果糖激酶反应中自振荡的实验研究可以大大简化，通过使用由少量反应组成的重构系统，该反应具有产物的不可逆汇和人工底物供应。
A simple kinetic model of an open monosubstrate enzyme reaction with substrate inhibition and product activation is described. A comparison between the model and the phosphofructokinase reaction shows a close resemblance between their dynamical properties. This makes it possible to explain qualitatively most experimental data on single-frequency oscillations in glycolysis. A mathematical analysis of the model has shown the following. In the model, at a definite relationship between the parameters, self-oscillations arise. The condition of self-excitation is satisfied more readily with a lower source rate, larger product sink rate constants, lower product-enzyme affinity and higher enzyme ac- tivity. Self-oscillations exist only in a certain range of values of the parameter determining the degree of substrate inhibition. This range increases with decreasing source rate. Too strong or, conversely, too weak substrate inhibition leads to damped oscillations. The period of self-oscillations depends on the degree of substrate inhibition, the source rate, the sink rate constant, the enzyme activity, the affinity of the substrate and the product for the enzyme; it decreases with an increase in these values. With an increase in the relative sink rate constant the steady state amplitude of self-oscillations initially increases until a definite maximum is reached and then drops to zero. A self-oscillatory state in the phosphofructokinase reaction exists only when the maximum rate of this reaction is essentially higher than the source rate, and lower than the maximum rate of the reactions controlling the sink of the products. An experimental investigation of self-oscillations in the phosphofructokinase reaction may be considerably simplified by using a reconstituted system consisting of a small number of reactions with an irreversible sink of the products and artificial substrate supply.