白芷细胞外21kD钙调素结合蛋白的生理功能初探

利用Ｓｅｐｈａｄｅｘ Ｇ１００ 及ＣＭＳｅｐｈａｒｏｓｅ层析法，从白芷悬浮培养细胞的胞外盐提液中纯化了２１ ｋＤ 钙调素结合蛋白（２１ ｋＤＣａＭＢＰ） ，测其等电点的ｐＨ 为８ ．９ ，紫外薄层扫描显示其纯度达９４ ％ 以上。以此蛋白为抗原，用免疫小鼠腹水法制备了特异性抗体。由纯化的２１ ｋＤＣａＭＢＰ及其特异性抗体研究其对白芷悬浮培养细胞增殖的影响，结果表明：加入外源纯化的２１ ｋＤＣａＭＢＰ 抑制细胞增殖，半抑制浓度约８ μｇ／ｍｌ；而加入２１ ｋＤＣａＭＢＰ特异性抗体却促进细胞增殖效应。推测胞外内源存在的２１ ｋＤＣａＭＢＰ在生理条件下可能具有参与调节胞外活化ＣａＭ 信号分子的浓度，从而调节胞外ＣａＭ 的生物学功能。

Preliminary Study on the Physiological Function of Extracellular 21 kD Calmodulin binding Protein from Angelica dahurica

The 21 kD calmodulin binding protein(CaMBP)was purified from extracellular extracts of suspension cultured cells of Angelica dahurica(Figs.1,2). There was only one band either in SDS PAGE or in IEF (Figs. 1,3). Its isoelectric point is pH 8.9 (Fig.3). The purity of the 21 kD CaMBP obtained was shown to be over 94% by gel scanning. The antibody against 21 kD CaMBP was prepared by immunizing rat against ascites. Western blotting showed that the antibody was specific to 21 kD CaMBP (Fig.4).The addition of purified 21 kD CaMBP to the cultured medium of suspension cultured cells of Angelica dahurica inhibited cell proliferation (Fig.5), whereas its antibody accelerated cell proliferation (Fig.6).Although the regulation of extracellular CaM activity might be complicated, the above results suggest that 21 kD CaMBP may act as a factor regulating the activation and deactivation of extracellular CaM by binding to or dissociating from it.