CELL MEMBRANE CONSTITUENTS CONCERNED WITH TRANSPORT MECHANISMS

Abstract

The biological membrane is a multiphasic, polyionic, regionally differentiated structure, the constituents of which are closely linked to the physiological and metabolic processes of the entire cell. Knowledge of the types of molecules, their orientation, and the relative importance of them for transport processes is still very fragmentary. The information at present available on the composition of the protoplast membrane, the red cell membrane, and the neuronal membrane is brought together and discussed in terms of the possible role in transport processes. A labile phosphate attached to protein or specific phosphatides or shared between them as a lipo-phosphoprotein complex is suggested as the intermediate in the active transport of sodium. The rapid phosphorylation of these constituents by ATP through the activity of membrane ATPase and their subsequent dephosphorylation could lead to rhythmic transitions in the configuration of membrane proteins and control active cation transport.