Reddy A S, Poovaiah B W
J Biochem. 1987 Mar;101(3):569-73. doi: 10.1093/jb/101.3.569.
The effect of inositol 1,4,5-trisphosphate (IP3) on Ca2+ release from microsomes of corn coleoptiles was investigated. Addition of micromolar concentrations of IP3 to Ca2+ loaded microsomes resulted in rapid release of 20-30% of sequestered Ca2+. Maximal and half maximal Ca2+ release occurred at 20 and 8 microM of IP3 respectively. Part of the Ca2+ released by IP3 was reaccumulated into microsomes within 4 min. The amount of Ca2+ released by IP3 was found to be dependent on free Ca2+ concentration in the incubation medium at the time of release. Maximum Ca2+ release was observed around 0.1 microM free Ca2+ concentration in the assay medium. These data suggest that IP3 might act as a second messenger in plants in a manner similar to animal systems by altering cytosolic levels of calcium.
研究了肌醇1,4,5 -三磷酸（IP3）对玉米胚芽鞘微粒体中Ca2+释放的影响。向加载了Ca2+的微粒体中添加微摩尔浓度的IP3，导致20% - 30%的螯合Ca2+快速释放。最大和半数最大Ca2+释放分别发生在20微摩尔和8微摩尔的IP3浓度下。IP3释放的部分Ca2+在4分钟内重新积累到微粒体中。发现IP3释放的Ca2+量取决于释放时孵育介质中的游离Ca2+浓度。在测定介质中游离Ca2+浓度约为0.1微摩尔时观察到最大Ca2+释放。这些数据表明，IP3可能通过改变细胞质钙水平，以类似于动物系统的方式在植物中充当第二信使。
