A number of peptidases and proteases have been identified in Escherichia coli. Although their specific physiological roles are often not known, some of them have been shown to be involved in: the maturation of nascent polypeptide chains; the maturation of protein precursors; the signal peptide processing of exported proteins; the degradation of abnormal proteins; the use of small peptides as nutrients; the degradation of colicins; viral morphogenesis; the inactivation of some regulatory proteins for which a limited lifetime is a physiological necessity. Some of these enzymes act in concert to carry out specific functions. At present, twelve peptidases and seventeen proteases have been characterized. The specificity for only a few of them is known. The possible roles and the properties of these enzymes are discussed in this review.

中文翻译：

---

大肠杆菌和鼠伤寒沙门氏菌的肽酶和蛋白酶。

在大肠杆菌中已经鉴定出许多肽酶和蛋白酶。尽管它们的具体生理作用通常是未知的，但其中一些已显示出参与：新生多肽链的成熟；蛋白质前体的成熟；出口蛋白的信号肽加工；异常蛋白质的降解；使用小肽作为营养素；大肠菌素的降解；病毒形态发生 某些必需寿命有限的生理调节蛋白的失活是生理必需的。这些酶中的一些协同作用以执行特定功能。目前，已经鉴定出十二种肽酶和十七种蛋白酶。仅其中少数几个的特异性是已知的。这些酶的可能作用和性质在本综述中进行了讨论。