大鼠不同组织的磷酸酶活性及钙调神经磷酸酶的钙依赖性

Study on the activity of phosphatases and the calcium dependence of calcineurin in different tissues of rat

【目的】观察钙调神经磷酸酶(CaN)、非钙调神经磷酸酶和镁离子调控的蛋白磷酸酶(PP2C)在大鼠不同组织中的活性及分布,以及CaN在不同组织中钙依赖性的特点。【方法】取正常大鼠不同器官组织,分步离心提取蛋白,应用紫外分光光度法测定磷酸酶在大鼠各组织中的活性及CaN在不同组织中的钙依赖性特点。【结果】CaN在脑组织中活性最高、其次为骨骼肌组织和心肌组织,而在肝脏组织中活性最低(P<0.01)。非钙调神经磷酸酶在脑和肝脏组织中活性较高,而骨骼肌和心肌组织中活性较低(P<0.01)。PP2C活性在脑组织中最高,骨骼肌和心肌组织次之,在肝脏中活性低(P<0.01)。钙依赖性实验表明,改变钙离子浓度时,各个组织中CaN活性均呈钟型改变,钙离子浓度过高可抑制CaN活性。【结论】钙调神经磷酸酶、非钙调神经磷酸酶和PP2C在大鼠体内均有广泛分布,可能参与多种器官组织的功能调节;钙依赖性实验结果表明大鼠不同器官组织中CaN对钙依赖性有共性,高钙引起的CaN活性抑制可能与CaN的内源性抑制物质有关。

To observe the activity and distribution of phosphatases and the calcium dependence of ealcineurin in different tissues of rat. [Method] The activity of calcineurin and other phosphatases in different tissues, and the activity of calcineurin in different calcium with uv-spectrophotometer. [Results] The activity of calcineurin in brain was higher than that in other tissues （6.81 ± 2.41, P 〈 0.01 ） . The activity of phosphatases in brain was higher than that in other tissues （7.59 ±1.93, P 〈 0.01 ）. The activity of PP2C in brain is higher than that in other tissues （4.55 ± 1.72, P 〈0.01）. As the concentration of calcium was added, the activity of calcineurin was increased. When pCa increased to 4.52, however, the activity of calcineurin was decreased. [Conclusion] These results suggest that the activity of phosphatases in brain are higher than in other tissues, and the result of calcium dependence presents a change of a bell shape.