Structural Factors in Respiratory Stimulation by Na + ‐ions in Escherichia Coli

While K + has a general stimulatory effect on respiration in Escherichia coli, Na + specifically enhances the rate of glutamate oxidation. Na + reduces the apparent K m of the glutamate‐oxidase system with respect to the substrate 90 times, but has no influence on V m. It is only effective when the cell structure remains intact, glutamate concentration is relatively low and hypotonic conditions prevail. In a cell‐free system the kinetic constants are not affected by Na + . Some implications of the above findings are discussed.