钙调蛋白磷酸酶(CN)是所知的唯一-种受Ca²﹢/CaM调节的蛋白磷酸酶,它是由一个催化亚基(Calcineutin A subunit，CNA)和一个Ca²﹢结合的调节亚基(Calcineutrin B subunit,CNB)组成的异二聚体,在人体免疫系统中起重要作用。它的调节亚基，CN B,被发现具有显著的抗癌作用。研究指出CN B不直接与肿瘤细胞结合，而与免疫细胞有结合。我们在前期实验中发现CN B与小鼠腹腔巨噬细胞有特异结合，在巨噬细胞质膜上存在CN B的受体。本实验中我们从小鼠体内收集腹腔巨噬细胞，通过细胞破碎和离心得到纯细胞质膜。然后溶解受体，利用凝集素亲和层析和CN B亲和层析等方法提取CN B受体，利用CN B受体与125Ｉ-CN B的结合实验筛选出含CNB受体的组分。最后对含CN B受体的组分进行SDS-聚丙烯酰胺凝胶电泳测定分析，并对各蛋白条带进行质谱鉴定，从而确认受体的属性。我们获得了巨噬细胞膜上的CN B受体，经质谱检测为X蛋白。

Calcineurin is the only known Ca²﹢/calmodulin-stimulated protein phosphatase.It is a heterodimeric enzyme consisting of a catalytic　subunit (CN A)and a Ca²﹢-binding regulatory subunit (CN B), which plays an important role in the human immune system. Its regulatory subunit, CN B ,on its own, was found to have a remarkable anticancer effect in mice. CN B was also found to bind to immune cells but not directly to tumor cells. In our previous studies. it was found that CN B bind specifically to peritoneal macrophage of mice. That is to say, there is CN B membrane receptor on macrophage. In the study, we collect peritoneal macrophage from mice and obtain pure membrane totally by broking cells and centrifuge. Then the receptors are dissolved and extracted by WGA-chromatography and CN B-chromatography. Then we obtain the components containing CN B receptors by the experiment in which CN B receptors bind to125Ｉ-CN B.At last,we analyze the components containing CN B receptors with SDS-Polyacarylamide Gel Electrophoresis, and analyze the protein bands by mass spectrometry to acknowledge the property of the receptors. We have obtained CN B membrane receptor from macrophages and demonstrated that it is X protein by mass spectrometry.