CARBOHYDRATE-METABOLISM IN DICTYOSTELIUM-DISCOIDEUM .1. MODEL CONSTRUCTION

A model of the transitional changes which occur in fluxes and metabolite concentrations during the course of differentiation of Dictyostelium discoideum is constructed, based on extensive experimental data collected from D. discoideum. Input to the model includes metabolite compartmentation and fluxes, determined by radiotracer analyses, and enzyme mechanisms and constants. This transition model reproduced experimentally measured changes in metabolite concentrations over the last 15 hr of differentiation. The real test of a mathematical model is its ability to correctly predict the effects of an altered environment or a mutation. This model demonstrates that ability. Constraints on model parameters are also examined, and many of the altered parameters result in a model which is unable to reproduce experimental data. These results imply that the model represents many aspects of metabolism in vivo and will provide a means of examining rate-limiting events during differentiation and aging of this organism.