钙调磷酸酶（Calcineurin,CN）是目前所知唯一依赖Ca2+/CaM的ser/thr蛋白磷酸酶。该酶由A、B二亚基以1:1的比例组成异二聚体，A亚基（CNA）是催化亚基；B亚基（CNB）是调节亚基，能促进CNA的活性，CN在生物体免疫系统和细胞调亡中具有重要的生理功能。CNB作为CN的调节亚基，分子量小，性质稳定。本实验室对CNB的生物学功能做了一些探讨，发现其有抑制肿瘤生长的潜能。为了开发应用CNB，本室已构建了重组人CNB（rhCNB）的基因工程表达系统，在大肠杆菌中得到高表达。本实验室已对rhCNB的发酵、纯化和药理药效做了大量的探讨，纯化工艺已经基本成熟，药效药理实验也取得了一些基本数据，为了进一步完善rhCN B的临床前研发资料，为中试开发和申请临床实验准备条件，本论文在在已取得的部分数据的基础上对rhCNB纯化工艺中对产品中内毒素含量的控制做了一些探索，对制备的产品做了部分质量鉴定，并用制备的药品对rhCNB进行了部分基本药理研究。全文共分两个部分：rhCNB药品制备、纯化工艺的进一步改进和rhCNB抗肿瘤的部分临床前药理研究。1. 药品制备部分：为了达到生物制品的质量标准，在纯化工艺中对器皿处理、试剂灭菌、规范操作等方面做了一些改进了，获得了纯度较高（毛细管电泳和HPLC检测达98％以上），内毒素检测基本合格的产品：终产品内毒素含量为13.83EU/mg（低于10 EU/mg合格），进一步通过Hiload 16/60 superdex 75 prep grad柱层析的样品内毒素含量为6.3EU/mg（低于10 EU/mg合格）。PNPP和同为素标记的RII活性检测发现rhCNB活性相比以前比较稳定并略有提高。2. 由于rhCNB产品质量的提高，在对其急性毒性研究中，发现在最佳剂量的208倍时对balb/c小鼠没有致死作用，不引起内脏明显病变，说明rhCNB急性毒性低。在已有的关于rhCNB药理药效实验数据的基础上，继续对rhCNB的抗肿瘤功能作一些探讨。对rhCNB对H22腹水瘤和H22实体瘤生长的抑制做了进一步研究。rhCNB对H22实体瘤和腹水瘤均有一定的防治作用,对实体瘤的抑制率达50%以上，对腹水瘤的生命延长率达75%以上。同时对rhCNB和本室新构建的CNBm单体突变体和4g二聚体突变体在抑制肿瘤生长方面做了一些比较，发现rhCNB的抗肿瘤能力强于新构建的两个突变体。

Calcineurin(CN) is the only serine/threorine protein phosphatase, under the control of Ca2+/Camodulin, plays a critical role in the coupling of Ca2+ signals to cellular responses. Regardless of its source, CN is always a heterodimer of a 61KDa catalytic subunit, calcineurin A (CNA), which tightly bounds to a 19KD regulatory subunit, calcineurin B(CNB). CN plays a crucial role in the immunity activation pathway and the cell apoptosis by the regulation of Ca2+.CNB is a small molecule with stable characteristics and can promote the activity of CN. Our laboratory has constructed the Gene Engineering Expression System of recombinant human CNB (rhCNB), which is expressed in Escherichia coli.. Some research suggested that rhCNB has potent preventive action against some kinds of cancer by studying on it’s biology function.Our laboratory has studied the ferment and、purify technique and anticancer potention of rhCNB. To develop and apply rhCNB, this paper did some further research in the purification and medical function of rhCNB .This paper includs two parts:1. We improve the purification of rhCNB at the disposal of the vessal，the antisepsis of the reagent ,and manipulating seriously. And we got the production meeting the quality of the recombinant drug .The purity of rhCNB is 98% and the structure is identical with natural CNB and the quantity of endotoxins in rhCNB is lower than before. 2. With the promotion of the quality of the production, rhCNB did not have much side effect on the liver and spleen in mice, compared with the control group. And acutetoxicity result shows that rhCNB’s toxicity is very, very low. The mice blood sample also demonstrated rhCNB was not as harmful as the cytotoxicity drug CTX.. Animal experiment was demonstrated that rhCNB has the inhibition function to H22 solid tumor and H22 liver cancer ascites tumor in mice. The inhibiton rate and the lengthening rate of life were over 50% and 75% with appropriate dosage. Compaerd with the other two mutants,the wild rhCNB showed stronger anticancer function. The results showed that rhCNB may play an important role in cancer prevention.