钙调素与细胞膜上Ca^（2＋）－ATP_（ase）结合域之间亲和性常数的测算

Measurement and calculation of affinity constant in between calmodulin and cell membiane Ca￣(2+) -ATP_(ase) binding domain

钙调素（Ｃａｌｍｏｄｕｌｉｎ，ＣａＭ）是一种多功能的酶调节物。Ｃａ２＋－ＣａＭ复合物可激活Ｃａ２＋－ＡＴＰａｓｅ，并触发Ｃａ２＋从细胞内移出或进入肌浆网内，以维持细胞内钙的平衡。Ｃａ２＋－ＣａＭ与Ｃａ２＋－ＡＴＰａｓｅ之间的相互作用可用亲和性常数来衡量。本文应用ＢＣＡ方法测定钙调素的浓度，应用ＳＤＳ－ＰＡＧＥ电泳技术测定钙调素的分子量，再用钙调素滴定ＤＣ２０Ｗ，同时测定相应的荧光，从而决定出两者相互作用的亲和性常数。

The interaction between calmodulin and calmodulin binding domain of cell membrane can be characterized by affinity constant.In the present study,calmodulin concentration and molecular weight of calmodul in were determined by BCA method and SDS-PAGE electrophoresis technique, respectively. In addition, DC20W was titrated with calmodulin and fluorescence intensity was measured by fluorescence spectrometer. Finally,the method introduced by Stinson and Holbrook was applied to calculate the affinity constant.