Tenu J P, Ghelis C, Yon J, CHevallier J
Biochimie. 1976;58(5):513-9. doi: 10.1016/s0300-9084(76)80220-9.
Binding of the nucleotides ATP and ADP by preparations of sarcoplasmic reticulum was investigated by the method of flow dialysis. For ATP, experimental data could not be analyzed directly in terms of binding since a significant though small amount of hydrolysis could be observed even in presence of EDTA. ADP binding could be analyzed and gave a dissociation constant of 10-20 muM at neutral pH, and a stoichiometry of 0.35 - 0.45 per mole ATPase. The possible significance of this stoichiometry is discussed. Similar experiments were performed after ethoxyformylation of sarcoplasmic reticulum which inhibits the Ca2+ dependnet ATPase activity. The results confirmed the inhibition of ATP hydrolysis and pointed to a considerably reduced affinity for nucleotides. The method based on the measurement of dialysis rates is convenient, and accurate enough to detect the effects of chemical modification on sarcoplasmic reticulum membranes.
采用流动透析法研究了肌浆网制剂对核苷酸ATP和ADP的结合情况。对于ATP，由于即使在存在乙二胺四乙酸（EDTA）的情况下也能观察到显著但少量的水解，因此实验数据无法直接根据结合情况进行分析。ADP结合情况可以进行分析，在中性pH值下解离常数为10 - 20微摩尔，每摩尔ATP酶的化学计量比为0.35 - 0.45。讨论了这种化学计量比可能的意义。在对肌浆网进行乙氧基甲酰化以抑制Ca2 + 依赖性ATP酶活性后进行了类似实验。结果证实了ATP水解受到抑制，并表明对核苷酸的亲和力大幅降低。基于透析速率测量的方法很方便，并且足够准确以检测化学修饰对肌浆网膜的影响。
