Prediction of Oscillations in Glycolysis in Ethanol Consuming Erythrocyte-Bioreactors

A mathematical model of energy metabolism in erythrocyte-bioreactors loaded with alcohol dehydrogenase and acetaldehyde dehydrogenase was constructed and analyzed. Such erythrocytes can convert ethanol to acetate using intracellular NAD and, thus, can be used to treat an alcohol intoxication. Analysis of the model reveals that the rate of ethanol consumption by the erythrocyte-bioreactors increases proportionally to activity of incorporated ethanol-consuming enzymes until their activity reaches a specific threshold level. When the ethanol-consuming enzyme activity exceeds this threshold, the steady state in the model becomes unstable and the model switches to an oscillation mode caused by a competition of glyceraldehyde phosphate dehydrogenase and ethanol-consuming enzymes for NAD. An amplitude and period of metabolite oscillations first increase with the increase in the activity of e encapsulated enzymes. A further increase in these activities leads to a loss of the glycolysis steady state, and a permanent accumulation of glycolytic intermediates. The oscillation mode and the loss of the steady state can lead to osmotic destruction of erythrocyte-bioreactors due to an accumulation of intracellular metabolites. Our results demonstrate that the interaction of enzymes encapsulated into erythrocyte-bioreactors with erythrocyte metabolism should be taken into account in order to obtain an optimal efficacy of these bioreactors.