Facilitated transport via carrier-mediated diffusion in membranes: Part I. Mechanistic aspects, experimental systems and characteristic regimes



Carrier-mediated transport in membranes as a globally nonreactive process is distinguished from film theory with chemical reaction and other facilitated diffusion phenomena. With the concept of stoichiometric and system invariants, an approach is developed for the analysis of carriersediated transport with multiple permeants involving multiple reactions in the membrane. Approximate solutions of the requisite differential equations according to the relative importance of diffusion and reaction rates are reviewed, as well as typical experimental studies. Criteria for evaluating whether a membrane is in the diffusion or equilibrium regime are given, and, in the latter case, the effects of some system parameters are given, for example, binding constants, competitive permeants.