牛凝乳酶原基因在大肠杆菌中的表达  

Expression of Calf Prochymosin in Escherichia coli

作　　者：张渝英[1] 周炜 刘年娟 杨开宇[1] 

机构地区：[1]中国科学院微生物研究所

出　　处：《生物工程学报》1991年第3期195-200,共6页Chinese Journal of Biotechnology

摘　　要：以Tac为启动子构建了牛凝乳酶原B基因表达质粒pTaAC,转化大肠杆菌JM105,对数生长期加入0.1mmol/L IPTG能明显诱导凝乳酸原的产生。基因表达除受IPTG的影响外,也受温度的调节控制。在30℃培养,IPTG存在时,凝乳酶原产量极低;在42℃无IPTG的条件下,基因也能表达。按电泳扫描计算凝乳酶原蛋白占细胞可溶性总蛋白量的12—19%,按ELISA法测定凝乳酸原产量为80—100mg/L,经变性、复性及酸化有活性的凝乳酶产量为14—20mg/L。The expression plasmid pTaAC containing Tac promoter and calfprochymosin B gene was constructed and transformed into E. coli JM105. Addition of 0.1mmol/L IPTG into the culture at logarithmic phaseinduced the production of prochymosin markedly. The expression ofprochymosin gene was regulated by temperature in addition to the indu-cer IPTG. At 30℃ in the presence of IPTG prochymosin was barelydetected, whereas at 42℃ in the absence of IPTG a relatively high levelof prochymosin was found. The expressed protein was estimated to be12--19% of total cell proteins by electrophoresis analysis or 80--100mg/Lby ELISA. The yield of active chymosin was 14--20mg/L after denatu-ration, renaturation and activation.

关 键 词：牛凝乳酶原 基因表达 

分 类 号：Q782[生物学—分子生物学]