Abstract: Objective Objective To express the beta carbonic anhydrase（β?CA）of Schistosoma japonicum，and analyze its catalytic activity. Methods Methods The cDNA and amino sequence which may encode β?CA of S. japonicum were obtained by the bioinformat? ics?method，and then the cDNA sequence was cloned into prokaryotic expression vector pET?32a （+）and expressed. After exam? ining by SDS?PAGE and Western blotting，the recombinant protein was purified by Ni?affinity chromatography and the catalytic activity was determined. Results Results The sequence Sjp_0056790.1 took on the conservative position of β?CAs. The PCR and re? striction enzyme digestion confirmed the construction of recombinant plasmid pET?32a （+） ?SjaCA. SDS?PAGE and Western blot? ting analyses showed that the molecular weight of recombinant protein was about 38 kDa as expected，and it could be recognized by anti?His tag antibody. The catalytic activity determining revealed that the recombinant protein SjaCA owned the carbonic an? hydrase activity. Conclusion Conclusion Sjp_0056790.1 encodes the β?CA of S. japonicum，and the β?CA with catalytic activity is suc? cessfully expressed，so it lays a foundation for the subsequent research of pharmacological inhibition，providing theoretic basis for searching and developing a new feasible anti?schistosome drug

Key words: Schistosoma japonicum, β?carbonic anhydrases（β?CA）, Drug target, Expression, Determination of catalytic activity

摘要： 目的 目的 原核表达日本血吸虫 （Schistosoma japonicum） 潜在的药物靶点β?碳酸酐酶 （β?CA） 并测定其催化活性。 方法 方法 根据β?CA保守序列， 在日本血吸虫基因组中鉴定β?CA序列， 核酸序列全合成后将其导入原核表达系统进行融合 表达。SDS?PAGE及Western blotting鉴定表达蛋白后， 采用Ni亲和层析方法纯化目的蛋白， 并测定碳酸酐酶活性。 结 结 果 果 cDNA序列Sjp_0056790.1具有β?CAs的保守序列； 成功将该核酸序列导入重组表达载体pET?32a （+） ?SjaCA中； SDS? PAGE和Western blotting检测结果显示融合蛋白分子量大小约为38 kDa； 碳酸酐酶活性测定结果显示该蛋白具有碳酸酐 酶活性， 且该活性受乙酰唑胺抑制。 结论 结论 Sjp_0056790.1编码日本血吸虫β?CA， 本研究成功表达了具有催化活性的日 本血吸虫的β?CA， 为后续的药物筛选奠定了基础。

关键词: 日本血吸虫, β?碳酸酐酶 （β?CA）, 药物靶点, 表达, 活性测定