KINETICS OF ACTIVE-TRANSPORT IN BIOLOGICAL-MEMBRANES - ROLE OF BARRIER FLUCTUATIONS

The role of barrier fluctuations in the membrane enzymatic processes, among others in the active transport of ions through cell membranes is examined. Membrane electric potential plays the role of a barrier hei ght (activation energy)for enzymes embedded in the cell membrane. This barrier height can be modulated either by internal fluctuations at by superimposed from without external electrical fields, either random o r periodic. Measurements of the changes in reaction yield, or in ionic currents, governed by these enzymes (ionic pumps) can be used as tool s for determining the parameters describing enzymatic action. Barrier fluctuations can change considerably the yield, including the inversio n of the direction of transmembrane currents.