Why does <i>Escherichia coli</i> recycle its cell wall peptides?

This review discusses the phenomenon of recycling of cell wall peptides. It is a major, though non‐essential, pathway of the cell and is required for induction of β‐lactamase. Consequently, the recycling pathway is viewed as a possible signalling vehicle, informing the cell of the condition of the murein sacculus, an essential structure existing outside the cell itself. As the study of this phenomenon is in its infancy, several speculations are offered for a possible regulatory function.