微小毛霉凝乳酶基因的定点突变及突变菌株的筛选  

Site-directed mutagenesis of recombinant mucor pusillus chymosin and screening of mutant strain

作　　者：王茜[1] 王昕[1] 张杰[2] 李倬林[2] 李铁柱[2] 

机构地区：[1]吉林大学生物与农业工程学院,长春130022 [2]吉林省农业科学院农产品加工研究所,长春130124

出　　处：《中国乳品工业》2015年第2期16-19,共4页China Dairy Industry

基　　金：国家自然科学基金青年科学基金(31101245);吉林省自然科学基金项目资助(20150101087JC);吉林省重大科技攻关专项(20140203014NY);吉林省科技发展计划项目(20140204051YY)资助

摘　　要：为了提高重组微小毛霉凝乳酶凝乳特性,对微小毛霉凝乳酶基因进行定点突变,分析了不同突变方案对凝乳活性、蛋白水解活性、酶的热稳定性的影响。以此为指标筛选到了突变体T218S菌株一株,其所产凝乳酶凝乳活力及C/P比值为52.35 U/m L和29.03,分别较改造前提高了23.2%和233.7%;非特异性水解活力由改造前的4.90 U/m L降低到1.80 U/m L,降低了63.3%。In order to improve the curd characteristics of recombinant Mucor pusillus rennet, this study conducted site directed mutagenesis of Mucor pusillus chymosin gene and analyzed the impacts of different mutation schemes on milk clotting activity, proteolytic activity and the thermal stability. Based on the above indexes we screened mutant strain T218 S strain, whose enzyme rennet curd activity and C/P ratio reached to 52.35 U/m L and 29.03, increased by 23.2% and 233.7% respectively with that before the transformation; the non-specific hydrolysis activity decreased to 1.80 U/m L, with a decrease by 63.3% compared with 4.90 U/m L before the transformation.

关 键 词：微小毛霉凝乳酶 定点突变 凝乳活性 水解活性 热稳定性 

分 类 号：Q814[生物学—生物工程]