目的 探讨pH值、聚乙二醇（polyethylene glycol，PEG）含量和离心条件对PEG4000粉末用于去除人C1酯酶抑制剂（C1 esterase inhibitor，C1-INH）制备原料中的IgM效果的影响，并通过对羧甲基（carboxymethyl，CM）离子交换层析中洗脱盐离子浓度的筛选，分离活性与非活性C1-INH。方法 向不同pH值的C1-INH制备原料中加入不同质量分数的PEG4000，于不同条件下离心后，用特定蛋白检测仪对离心后上清液中IgM和C1-INH含量进行检测，确定PEG沉淀法纯化C1-INH的最佳条件。将离心后上清液调节pH后作为CM离子交换层析上样样品，使用不同盐离子浓度的洗脱液对活性C1-INH进行分离，确定最佳的盐离子浓度。结果 在弱酸性pH（6.8）下，当PEG4000质量分数为12%，离心条件15 000×g、25 ℃、20 min时，IgM去除率>99%，且C1-INH的回收率>80%；在盐离子浓度为200 mmol/L时，产物中C1-INH的比活性最大（4.43 IU/mg），且绝大多数杂质蛋白得以去除。结论  优化条件下PEG4000能有效去除C1-INH制备原料中的IgM，且能保持较高的C1-INH回收率；CM离子交换层析能对活性与非活性C1-INH进行有效分离，并去除大多数杂质蛋白。

 Objective  To probe the effects of pH, content of polyethylene glycol (PEG) and centrifugal conditions on IgM removal  from raw materials of human C1 esterase inhibitor (C1-INH) using PEG4000 powder, and to separate active and inactive C1-INH by screening the salt ion concentration in wash step of carboxymethyl (CM) ion exchange chromatography. Methods  Raw materials of C1-INH at different pH were mixed with PEG4000 of different mass fractions, and centrifugated under different conditions. IgM and C1-INH contents in the supernatant were detected by specific protein detector to determine the optimal conditions for PEG precipitation purification of C1-INH. The centrifugation supernatant was used as loading sample for CM ion exchange chromatography after pH adjustment. The eluent with different salt ion concentrations was used to separate the active C1-INH to determine the optimal concentration of salt ions. Results  Under the condition of weak acidic pH (6.8), 12% PEG4000 mass fraction and 15 000×g, 20 min centrifugation at 25 ℃, IgM removal rate was >99% and the recovery rate of C1-INH was >80%. At salt ion concentration of 200 mmol/L, the specific activity of C1-INH in the product reached the maximum (4.43 IU/mg), and most impurities were removed. Conclusions  Under optimal conditon,PEG4000 can effectively remove IgM from C1-INH raw materials and maintain a high recovery rate of C1-INH, and CM ion exchange chromatography can effectively separate the active and inactive C1-INH as well as remove most impurities.