Kinetics of Tracer Exchange

Abstract

It was shown several times before (p. 70, p. 153) that the kinetics of transmembrane movement are greatly simplified if the process studied is first-order, i.e., if the rate of the movement of the substance studied is directly proportional to its concentration. It was also shown that, in addition to conditions of very low saturation of the transport systems when the movement proceeds as an approximation to a diffusion process, first-order kinetics can be attained by the use of tracers. The use of tracers provides an additional bonus in that it makes it possible to follow unidirectional fluxes of a substance under conditions when the substance moves across a membrane in both directions.