Sylakova A I, Konoplyts'ka O L, Huseva T N
Ukr Biokhim Zh. 1975 Jan-Feb;47(1):31-5.
A comparative study was carried out in the properties of ATPase system of the skeletal muscle nuclei in the rabbits in norm and with experimental muscular dystrophy conditioned by E-avitaminosis. It is shown that in the system, containing 1.5 mM of MgCl2, ATPase system of the nuclei is activated by sodium and potassium ions. In norm maximum activation is observed with their presence in the medium, the concentration being 80 and 70 mM, respectively. With experimental muscular dystrophy maximum activating concentrations decrease and are equal for both cations - 30 mM. Activation of the enzymatic system by these ions is specific because the introduction of equimolar quantities of cholin-chloride or lithium, cesium ions instead of sodium ions into the incubation medium evokes no activation of the ATPase system of the rabbit skeletal muscles both in norm and with experimental muscular dystrophy. A simultaneous presence of sodium and potassium ions in optimum concentrations in the incubation medium makes for an increase of ATPase activity to the same extent as the presence of one of these cations. Oubain, a specific inhibitor of Mg2+, Na+, K+- ATPase, taken in the concentrations of 10(-4) and 10(-3) M did not decrease the intensity of ATP hydrolysis and its activation conditioned by the presence of sodium or potassium. A conclusion is made that Mg2+, Na+, K+-ATPase taking part in the work of "sodium pump" is absent in the nuclei of skeletal muscles.
对正常及因维生素E缺乏症引发实验性肌肉萎缩的家兔骨骼肌细胞核ATP酶系统的特性进行了一项对比研究。结果显示，在含有1.5 mM氯化镁的体系中，细胞核的ATP酶系统被钠离子和钾离子激活。在正常情况下，当培养基中存在这两种离子时可观察到最大激活效果，其浓度分别为80 mM和70 mM。在实验性肌肉萎缩时，最大激活浓度降低，且两种阳离子的最大激活浓度相等，均为30 mM。这些离子对酶系统的激活具有特异性，因为在孵育培养基中引入等摩尔量的氯化胆碱或锂、铯离子来替代钠离子，无论是在正常还是实验性肌肉萎缩情况下，都不会引起家兔骨骼肌ATP酶系统的激活。孵育培养基中同时存在最佳浓度的钠离子和钾离子时，ATP酶活性的增加幅度与仅存在其中一种阳离子时相同。浓度为10(-4)和10(-3) M的Mg2+、Na+、K+-ATP酶特异性抑制剂哇巴因，并不会降低ATP水解的强度及其因钠离子或钾离子存在而产生的激活作用。由此得出结论，参与“钠泵”工作的Mg2+、Na+、K+-ATP酶不存在于骨骼肌细胞核中。
