Osmolarity of periplasm when in water

Range ~170 mosm
Organism Bacteria Escherichia coli
Reference Stock JB, Rauch B, Roseman S. Periplasmic space in Salmonella typhimurium and Escherichia coli. J Biol Chem. 1977 Nov 10 252(21):7850-61 p.7858 right column bottom paragraphPubMed ID334768
Method The cytoplasmic, periplasmic, and total cell volumes were all derived from the distributions of solutes in cell suspensions, The rationale is illustrated in Fig. 1. Inulin, because it is large, cannot penetrate the outer membrane and is located only in the extracellular fluid. Sucrose, without the aid of a permease, cannot cross the plasma membrane and is located only in the periplasm and extracellular fluid. Water moves freely throughout the cell it is located in the cytoplasm, periplasm, and extracellular fluid.
Comments "The situation with cells in water was the best defined: the osmotic strength of the medium was essentially zero: that of the periplasm approximately 170 mosM. The sum of the molal concentrations of the material dissolved in periplasmic water must, therefore have been at least 170mmolal."
Entered by Uri M
ID 108561