Tsuchiya K, Gomi K, Kitamoto K, Kumagai C, Tamura G
Research Institute of Brewing Resources Co. Ltd., Tokyo, Japan.
Appl Microbiol Biotechnol. 1993 Nov;40(2-3):327-32. doi: 10.1007/BF00170388.
Active calf chymosin was secreted from Aspergillus oryzae transformants when the chymosin cDNA was expressed under the control of glucoamylase gene (glaA) promoter. Secreted prochymosin was autocatalytically activated to the chymosin (0.07-0.16 mg/l). Western blot analysis showed that a secreted protein immunoreactive with an anti-chymosin antibody was of similar size to authentic chymosin. Northern blot analysis revealed that mRNA of the chymosin cDNA was expressed at as high level as that of the glaA gene. The size and the level of the transcript were different among transformants, due to the integration position of the plasmid on the chromosome.
当凝乳酶cDNA在糖化酶基因（glaA）启动子的控制下表达时，米曲霉转化体分泌出活性小牛凝乳酶。分泌的凝乳酶原被自动催化激活为凝乳酶（0.07 - 0.16毫克/升）。蛋白质印迹分析表明，与抗凝乳酶抗体发生免疫反应的分泌蛋白大小与天然凝乳酶相似。Northern印迹分析显示，凝乳酶cDNA的mRNA表达水平与glaA基因的表达水平一样高。由于质粒在染色体上的整合位置不同，转化体之间转录本的大小和水平存在差异。
