目的　表达与纯化结核分支杆菌katG 蛋白,为深入研究异烟肼耐药机制奠定基础。方法　将含有katG 基因的pET24bkatG 表达载体转化大肠杆菌BL21(DE3) 菌株,在异丙基硫代βD半乳糖苷(IPTG) 诱导下表达,分别对不同诱导时间的表达产物进行SDSPAGE 以及考马斯亮蓝染色。获得稳定的高表达菌株后采用Xpress TM蛋白纯化系统对超声破菌液进行纯化。最后对纯化产物进行过氧化氢酶活性的初步检测。结果　对诱导后的重组大肠杆菌菌液进行十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDSPAGE) 以及考马斯亮蓝染色后发现相对分子质量约为80 000 。表达蛋白量约占总蛋白量的17.7% 。对重组katG基因表达产物进行纯化的结果发现,以350 m mol/L咪唑洗脱时的纯化效果最理想,蛋白纯度可达90 % 以上。对表达产物进行过氧化氢酶活性初步检测证明,重组的katG 基因产物具有过氧化氢酶活性。结论　通过pET24bkatG 表达质粒转化大肠杆菌可获得基因重组的katG 高表达菌株,表达产物具有一定酶活性,经纯化后可达到较高的纯度 Objective To express and purify katG protein of Mycobacterium tuberculosis and lay a foundation for further study on the mechanism of isoniazid resistance. Methods The pET24bkatG expression vector containing katG gene was transformed into E. coli BL21 (DE3) strain and expressed under the induction of isopropylthiDgalactoside (IPTG). The expression products of different expression time were induced SDS  PAGE and Coomassie brilliant blue staining. After a stable, highly expressed strain was obtained, the sonication solution was purified using the Xpress ™ Protein Purification System. Finally, the purified product was tested for catalase activity. Results The relative molecular weight of the recombinant E. coli after induced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDSPAGE) and Coomassie brilliant blue staining was about 80 000. The amount of expressed protein accounted for about 17.7% of the total protein. Purification of the recombinant katG gene expression product showed that the best purification efficiency was obtained when the imidazole was 350 m mol / L, the purity of protein was over 90%. The preliminary detection of catalase activity of the expressed product demonstrated that the recombinant katG gene product has catalase activity. Conclusion Recombinant katG highly expressed strain can be obtained by transforming pET24b-katG plasmid into E.coli. The expressed product has some enzymatic activity and can be purified to a higher purity