筋小胞體의 Ca 吸收能과 ATPase 活性을 各種 濃度의 K, Mg, caffeine, procaine, 및 quinine 존재하에서 측정하였다. ATP不在下에서 Ca吸收能은 K 또는 Mg의 농도가 증가함에 따라 低下된다. 그러나 ATP 존재하에서의 Ca吸收能은 K의 농도에는 거의 영향을 받지 않고, Mg의 농도가 증가함에 따라 현저히 증가한다. Caffeine과 procaine은 ATP 존재하의 Ca吸收能을 阻害하지만 quinine은 阻害하지 않는다. ATPase 活性은 K의 농도에는 영향을 받지 않으나 Mg의 존재에 의하여 증가된다. Caffeine, procaine 및 quinine은 이 活性에 거의 영향을 미치지 않는다.
The Ca uptake by the fragmented sarcoplasmic reticulum of the rabbit skeletal muscle was measured under various concentrations of K, Mg, Caffeine, procaine and quinine. The ATPase activity of this reticular membrane was measured under the same conditions simultaneously. The saturation of Ca uptake was almost completed within 1 minute. The Ca uptake was inhibited by high concentrations of K (above 50 mM) and Mg (above 1 mM)in the absence of ATP. When ATP is present, however, the Ca uptake did not reflect the concentration of K, while it increased greatly as the concentration of Mg was increased. Caffeine and procaine caused the inhibition of Ca uptake in the presence of ATP, but quinine did not. The ATPase activity of the membrane was little affected by the concentration of K, while it was enhanced in the presence of Mg. Caffeine, procaine and quinine did not influence the ATPase activity.
