The Mechanism of the Action of Caffeine on Sarcoplasmic Reticulum
The Mechanism of the Action of Caffeine on Sarcoplasmic Reticulum
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咖啡因对肌浆网的作用机制
DOI：
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发表时间：
1968
期刊：
影响因子：
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通讯作者：
A. Weber
中科院分区：
文献类型：
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作者：
A. Weber
有证据表明，咖啡因不作用于线粒体钙摄取系统，其作用不能归因于腺苷3 '，5'-磷酸的积累。描述了两种不同的咖啡因效应。在高ATP浓度下，咖啡因降低ATP水解和Ca流入之间的耦合。它或者抑制流入而不抑制ATP水解速率，或者刺激ATP酶活性而不刺激Ca流入。这些高ATP浓度（远高于转运ATP酶饱和所需的浓度）通过累积的Ca大大降低了对转运系统的周转率的控制。在低ATP浓度下，当运输系统受到累积的Ca的最大控制时，咖啡因抑制ATP酶活性而不影响Ca流入的速率。
Evidence is presented that caffeine does not act on the mitochondrial Ca uptake system and that its effect cannot be attributed to the accumulation of adenosine 3',5'-phosphate. Two distinct caffeine effects are described. At high ATP concentrations caffeine decreases the coupling between ATP hydrolysis and Ca inflow. It either inhibits inflow without any inhibition of the rate of ATP hydrolysis, or it stimulates the ATPase activity without stimulating Ca inflow. These high ATP concentrations (much higher than needed for the saturation of the transport ATPase) greatly reduce the control of the turnover rate of the transport system, by accumulated Ca. At low ATP concentrations when the transport system is under maximal control by accumulated Ca, caffeine inhibits the ATPase activity without affecting the rate of Ca inflow.