The periplasmic space (or periplasm) is the region between the outer leaflet of the cytoplasmic membrane and the inner leaflet of the outer membrane of Gram negative bacterial cells. It is about 15 nm wide and contains a variety of proteins which allow the cell to carry out extracytoplasmic activities without diffusing away from the cell due to the impermeability of the outer membrane to proteins. Such proteins include: enzymes which hydrolyse polymers to be imported into the cell; chemoreceptors; those which are involved in the biosynthesis of peptidoglycan and the outer membrane from simple molecules transported out of the cytoplasm, and binding proteins for substrate transport.
- ↑ Madigan, Michael T., et al. Brock Biology of Microorganisms, Global Edition, Pearson Education Limited, 2017