Studies on ion distribution in living cells. II. Cooperative interaction between intracellular potassium and sodium ions.
New steady levels of K(+) and Na(+) ion in frog sartorius muscle were reached in 72 hr at 25 degrees C in environments containing 100-mM Na(+)-ion and K(+)-ion concentrations varying from near zero to 10 mM. These steady levels follow a pattern predicted by a cooperative adsorption isotherm presented in 1964. From a total of 13 sets of experiments carried out over a five year period, the average concentration of adsorption sites is 109 mumoles/g of fresh cells. The average intrinsic equilibrium constant for the Na --> K exchange is 135, and the average free energy of nearest neighbor interaction is 0.54 kcal/mole. These values are in good agreement with those obtained by Jones and Karreman from studies on canine carotid arteries.
D000327:Adsorption; D000818:Animals; D001001:Anura; D002462:Cell Membrane / Q000502:physiology; D007477:Ions / Q000378:metabolism; D008433:Mathematics; D008954:Models, Biological; D009132:Muscles / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013816:Thermodynamics; D013997:Time Factors
D007477:Ions; D012964:Sodium; D011188:Potassium