Theoretical analysis of a translocation-like model with saturable kinetics

A theoretical analysis of the initial rates of product appearance in both compartments of a specifically designed diffusion cell separated by an asymmetrical enzyme membrane is presented. Variable substrate concentrations and different substrate diffusional limitations were considered. Our analysis shows that, under specific conditions, not only a product accumulation occurs in the compartment opposite to that in which the reaction takes place, but that substrate saturable kinetics can be obtained. These product translocation-like kinetics appear similar to those observed with translocation processes reported for biological situations. For such phenomena, a key role of the diffusion layer surrounding a bioactive surface is proposed.