REGULATION OF GLYCOLYSIS IN MUSCLE. II. EFFECT OF STIMULATION AND EPINEPHRINE IN ISOLATED FROG SARTORIUS MUSCLE.
REGULATION OF GLYCOLYSIS IN MUSCLE. II. EFFECT OF STIMULATION AND EPINEPHRINE IN ISOLATED FROG SARTORIUS MUSCLE.
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肌肉糖酵解的调节。
DOI：
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发表时间：
1964
影响因子：
4.8
通讯作者：
C. Cori
中科院分区：
文献类型：
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作者：
S. Karpatkin;E. Helmreich;C. Cori
原则上，总速率可以通过“推”机制加速，使得反应序列1最初> 2，或者通过“拉”机制加速，使得反应序列2最初> 1，条件是酶未被底物饱和。在第一种情况下，将涉及磷酸化酶系统;在第二种情况下，磷酸果糖激酶反应。后一个反应实际上是不可逆的，因此超过它的酶促步骤（反应序列3）将不能有效地进行牵拉。第三种可能性是至少同时激活反应序列1和2，如果不是整个糖酵解链的话。葡萄糖6-磷酸，正磷酸盐，细胞内乳酸，乳酸在培养基中进行了测定，在实验中与肌肉刺激单冲击或与肾上腺素孵育。糖酵解速率可从10.通过不同频率的刺激使心率超过静息心率的100倍。乳酸盐形成与刺激频率成正比。葡萄糖g-磷酸盐水平和正磷酸盐浓度在每分钟18次收缩时几乎没有变化，尽管这种收缩率有利于心脏的收缩。
In principle, the over-all rate could be accelerated by a “push” mechanism, such that Reaction Sequence 1 > 2 initially or by a “pull” mechanism, such that Reaction Sequence 2 > 1 initially, provided that the enzymes are not saturated with substrate. In the first case, the phosphorylase system would be involved; in the second case, the phosphofructokinase reaction. The latter reaction is practically irreversible, so that enzymatic steps beyond it (Reaction Sequence 3) would not be effective in exercising a pull. A third possibility would be a simultaneous activation of at least Reaction Sequences 1 and 2, if not of the entire glycolytic chain. Glucose 6-phosphate, orthophosphate, intracellular lactate, and lactate in the medium were determined in experiments with muscles stimulated with single shocks or with muscles incubated with epinephrine. Rates of glycolysis could be increased from 10. to loo-fold over the resting rate by stimulation at different frequencies. Lactate formation was proportional to the frequency of stimulation. The glucose g-phosphate level and the concentration of orthophosphate showed little change up to 18 contractions per minute, although this rate of contraction pro-