54kD钙结合蛋白对血小板膜磷脂酶A_2的影响  

The Effect of 54kD Calcium-binding Protein on the Platelet Membrane-bound PLA_2WANG Tie-Lin; FEI Zheng and ZHUANG Qing-Qi

作　　者：王铁琳[1] 费正[1] 庄庆祺[1] 

机构地区：[1]上海医科大学药学院生物化学教研室

出　　处：《生物化学与生物物理学报》1996年第1期89-95,共7页

基　　金：国家自然科学基金

摘　　要：用钙离子沉淀和柱层析的方法从猪血小板中分离纯化到了一个分子量为５４ｋＤ、具有Ａｎｎｅｘｉｎ样生物学作用的钙结合蛋白，并用对钙离子有高度特异亲和力的偶氮胂试剂确定了该蛋白质具有钙结合能力。为了研究５４ｋＤ钙结合蛋白对猪血小板膜磷脂酶Ａ２的作用，我们用密度梯度离心方法制备了猪血小板膜，并用其作为酶和底物的材料，用游离脂肪酸的微量显色法建立了测定猪血小板膜结合的ＰＬＡ２活性的方法。我们的实验结果表明：５４ｋＤ钙结合蛋白在反应体系钙离子浓度低于１ｍｍｏｌ／Ｌ时，对膜结合的ＰＬＡ２具有激活作用；在钙离子大于１ｍｍｏｌ／Ｌ时；对膜结合的ＰＬＡ２具有抑制作用。并且抑制作用不随底物浓度的升高而降低．A 54kD calcium-binding protein was isolated from porcine platelet after calcium precipitation and chromatography. Its calcium-binding ability was proved by the Arasenzo Ⅲ binding analysis. In order to study the physiology role of calcium-binding protein in platelets, an experiment to study the effect of 54kD calcium-binding protein on the platelet membrane-bound PLA2 was designed. We isolated porcine platelet membrane by the two-phases system and developed a simple assay method for phospholipase A2 by the colorimetric micro-determination of long-chain fatty acid released by the enzyme. The results indicated that in the presence of 54kD CaBP the activity of porcine platelet membrane-bound PLA2 was stimulated with lower Ca2+ concentration (<1 mM), but inhibited when the Ca2+concentration was above 1 mM. The inhibiting effect of 54kD CaBP was not decreased with the increase of substrate concentration.

关 键 词：结合蛋白 54kD钙结合蛋白 血小板膜 磷脂酶A2 

分 类 号：Q513.02[生物学—生物化学]