COOPERATIVE INTERACTION AMONG SURFACE P- AND./-CARBOXYL GROUPS MEDIATING THE PERMEATION OF IONS INTO FROG MUSCLE

widely-held belief of full ionic dissociation in electrolyte solutions, I suggested that the degree of association with its counterion be-comes greatly increased if one species of the ions is fixed in space (Ling, 195 1, 1952). With this enhanced association, K', which differs from Na ' only in short-range attributes (e.g., polarizability, Born repulsion constants), can become preferentially adsorbed on the fixed p- and y-carboxyl groups of cell proteins. Such selective adsorption on cytoplasmic P-and y-carboxyl groups served as the founda-tion for a new theory for selective accumula-tion of K ' over Na ' in many living cells (Ling, 1952). Similar selective adsorption on cel