The critical concentration of actin in the presence of ATP increases with the number concentration of filaments and approaches the critical concentration of actin.ADP.
The critical concentration of actin in the presence of ATP increases with the number concentration of filaments and approaches the critical concentration of actin.ADP.
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ATP存在下肌动蛋白的临界浓度随着丝数浓度的增加而增加，并接近肌动蛋白.ADP的临界浓度。
DOI：
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发表时间：
1984
影响因子：
4.8
通讯作者：
E. Korn
中科院分区：
文献类型：
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作者：
D. Pantaloni;M. Carlier;M. Coué;A. Lal;S. Brenner;E. Korn
在ATP存在的情况下，稳定状态下的F-肌动蛋白在机械碎裂时部分解聚为新的稳定状态。定量地研究了临界浓度随纤维数浓度的增加而增加的规律。这些数据可以用一个模型来解释，在该模型中，在ATP存在的情况下，稳定状态下肌动蛋白结合-解离反应的首选途径涉及G-肌动蛋白的结合。三磷酸腺苷到细丝、三磷酸腺苷的水解和G-肌动蛋白的解离。ADP，然后慢慢转化为G-肌动蛋白。三磷酸腺苷。由于核苷酸在G-肌动蛋白上的缓慢交换，相应的G-肌动蛋白的量。ATP和G-肌动蛋白。ADP与F-肌动蛋白的稳定共存依赖于丝数浓度。当G-肌动蛋白与F-肌动蛋白在纤维的零数浓度时共存时，就会形成G-肌动蛋白。而G-肌动蛋白的临界浓度为G-肌动蛋白的临界浓度。ADP。在20℃、pH 7.8、0.1 mM CaCl2、1 mM MgCl2和0.2 mM ATP条件下，骨骼肌肌动蛋白的这两个极端临界浓度的值分别为0.35和8微米。用8微米直接测定G-肌动蛋白的临界浓度。ADP在ADP存在和不存在ATP的情况下聚合，不受裂解的影响。这些结果对于在改变丝数浓度的条件下比较临界浓度的实验具有重要的意义。
F-actin at steady state in the presence of ATP partially depolymerized to a new steady state upon mechanical fragmentation. The increase in critical concentration with the number concentration of filaments has been quantitatively studied. The data can be explained by a model in which the preferred pathway for actin association-dissociation reactions at steady state in the presence of ATP involves binding of G-actin . ATP to filaments, ATP hydrolysis, and dissociation of G-actin . ADP which is then slowly converted to G-actin . ATP. As a consequence of the slow exchange of nucleotide on G-actin, the respective amounts of G-actin . ATP and G-actin . ADP coexisting with F-actin at steady state depend on the filament number concentration. G-actin coexisting with F-actin at zero number concentration of filaments would then consist of G-actin . ATP only, while the critical concentration obtained at infinite number of filaments would be that for G-actin . ADP. Values of 0.35 and 8 microM, respectively, were found for these two extreme critical concentrations for skeletal muscle actin at 20 degrees C, pH 7.8, 0.1 mM CaCl2, 1 mM MgCl2, and 0.2 mM ATP. The same value of 8 microM was directly measured for the critical concentration of G-actin . ADP polymerized in the presence of ADP and absence of ATP, and it was unaffected by fragmentation. These results have important implications for experiments in which critical concentrations are compared under conditions that change the filament number concentrations.