Adunyah S E, Dean W L
Biochem Biophys Res Commun. 1985 May 16;128(3):1274-80. doi: 10.1016/0006-291x(85)91078-2.
Inositol (1,4,5) triphosphate (IP3) was observed to induce release of sequestered Ca2+ from crude human platelet membranes. This activity was also shown to be present in purified membranes enriched in Ca2+-ATPase activity. Maximal Ca2+ release occurred at 8 microM IP3 and half maximal activity was at 0.4 microM. Release was quite rapid and was complete by 40 s. Released Ca2+ was pumped back into the membrane vesicles and the rate of this reuptake was increased by the presence of phosphate. These results demonstrate that internal platelet membranes that possess an active Ca2+-pump will release sequestered Ca2+ in the presence of the second messenger IP3. IP3 did not induce release of Ca2+ from skeletal muscle sarcoplasmic reticulum when ATP was present.
已观察到肌醇（1,4,5）三磷酸（IP3）可诱导人血小板粗膜中储存的Ca2+释放。这种活性在富含Ca2+-ATP酶活性的纯化膜中也有表现。最大Ca2+释放在8微摩尔IP3时出现，半最大活性在0.4微摩尔时。释放相当迅速，40秒时完成。释放的Ca2+被泵回膜泡，并且这种再摄取的速率因磷酸盐的存在而增加。这些结果表明，具有活性Ca2+泵的血小板内部膜在第二信使IP3存在时会释放储存的Ca2+。当存在ATP时，IP3不会诱导骨骼肌肌浆网释放Ca2+。
