Doubell A F, Lazure C, Tremblay J, Thibault G
Department of Internal Medicine, Faculty of Medicine, University of Stellenbosch, Tygerberg, South Africa.
Cardiovasc Res. 1994 May;28(5):705-9. doi: 10.1093/cvr/28.5.705.
The role of calcium in the regulation of atrial natriuretic factor (ANF) secretion has focused attention on calcium binding proteins as regulatory components of the secretory machinery for ANF. Two members of the annexin family of calcium binding proteins have emerged as candidates for this role. The aim of this paper is to report the isolation, purification, and identification of another calcium dependent atrial secretory granule binding protein.
A 20 kDa calcium binding protein was isolated from rat cardiac tissue by affinity chromatography and purified by ion exchange high pressure liquid chromatography followed by reverse phase high pressure liquid chromatography. Identification of the protein was based on its electrophoretic mobility, chromatographic properties, amino acid composition, and ability to stimulate the activity of calmodulin dependent phosphodiesterase.
Analysis of this protein and its interaction with atrial secretory granules revealed that it was identical to calmodulin and that the calcium dependent interaction with atrial secretory granules takes place at physiological calcium concentrations.
The study identifies calmodulin as a calcium dependent atrial secretory binding protein. The interaction of calmodulin with atrial secretory granules at physiological calcium concentrations suggest a possible role for calmodulin in the regulation of ANF release from the secretory granules.
钙在心房利钠因子（ANF）分泌调节中的作用，使人们将注意力集中在钙结合蛋白作为ANF分泌机制的调节成分上。钙结合蛋白膜联蛋白家族的两个成员已成为这一角色的候选者。本文的目的是报告另一种钙依赖性心房分泌颗粒结合蛋白的分离、纯化和鉴定。
通过亲和层析从大鼠心脏组织中分离出一种20 kDa的钙结合蛋白，然后通过离子交换高压液相色谱，接着用反相高压液相色谱进行纯化。该蛋白的鉴定基于其电泳迁移率、色谱特性、氨基酸组成以及刺激钙调蛋白依赖性磷酸二酯酶活性的能力。
对该蛋白及其与心房分泌颗粒的相互作用分析表明，它与钙调蛋白相同，并且在生理钙浓度下发生与心房分泌颗粒的钙依赖性相互作用。
该研究确定钙调蛋白为一种钙依赖性心房分泌结合蛋白。钙调蛋白在生理钙浓度下与心房分泌颗粒的相互作用表明，钙调蛋白在调节ANF从分泌颗粒中释放方面可能发挥作用。
