RESUMO
Enzymatic redox reaction is modelled by a set of microgalvanic elements shorted out. It allows to use as the rate constant of enzymatic reaction the rate constant deduced for the electrode reaction with a limiting stage of electron transfer. The basic problem is to determine the nonequilibrium potential by the phase border enzyme/solution. A phenomenological model for determining the nonequilibrium adsorption dependent potential is suggested. The rate constant is deduced which depends on the adsorption of one of the substrates (activation or inhibition). This dependence is the same for the whole set of adsorption isoterms. A class of well known relationships of the initial rate of enzymatic reaction and the substrate concentration is obtained for a simple case of physical adsorption.