Burnett T J, Shankweiler G W, Hageman J H
J Bacteriol. 1986 Jan;165(1):139-45. doi: 10.1128/jb.165.1.139-145.1986.
Cells of Bacillus subtilis 168 (trpC2) growing and sporulating in a single chemically defined medium carried out intracellular protein degradation and increased their levels of intracellular serine protease-1 in a manner very similar to what had previously been reported for cells sporulating in nutrient broth. The results were interpreted to mean that these processes are intrinsic to sporulation rather than medium dependent. To determine the cause of these increases in specific activity of proteinases, we purified the protease, prepared rabbit immunoglobulins directed against it, and monitored changes in protease antigen levels by performing rocket immunoelectrophoresis. In cells sporulating in nutrient broth, the protease antigen levels increased about 7-fold, whereas the specific activity increased about 150-fold, for an activation of about 20-fold. In cells sporulating in the single chemically defined sporulation medium, the protease antigen increased about 10-fold, whereas the specific activity increased at least 400-fold, for an activation of about 40-fold. These results were interpreted to mean that a posttranslational event activated the protease in vivo; a previously described endogenous proteinase inhibitor was confirmed to be present in the strain used. Chloramphenicol added to the cultures inhibited both the increases in antigen levels and in the specific activity of the proteinase.
枯草芽孢杆菌168（trpC2）在单一化学成分明确的培养基中生长和形成芽孢时，会进行细胞内蛋白质降解，并以与先前在营养肉汤中形成芽孢的细胞所报道的方式非常相似的方式提高其细胞内丝氨酸蛋白酶-1的水平。这些结果被解释为意味着这些过程是芽孢形成所固有的，而不是依赖于培养基。为了确定这些蛋白酶比活性增加的原因，我们纯化了该蛋白酶，制备了针对它的兔免疫球蛋白，并通过进行火箭免疫电泳监测蛋白酶抗原水平的变化。在营养肉汤中形成芽孢的细胞中，蛋白酶抗原水平增加了约7倍，而比活性增加了约150倍，激活倍数约为20倍。在单一化学成分明确的芽孢形成培养基中形成芽孢的细胞中，蛋白酶抗原增加了约10倍，而比活性至少增加了400倍，激活倍数约为40倍。这些结果被解释为意味着翻译后事件在体内激活了蛋白酶；在所用菌株中证实存在一种先前描述的内源性蛋白酶抑制剂。添加到培养物中的氯霉素抑制了抗原水平的增加和蛋白酶的比活性。
