An analysis of the kinetic positions held by five enzymes of carbohydrate metabolism in Dictyostelium discoideum

Abstract

The role of five enzymes essential to differentiation in Dictyostelium discoideum has been analyzed by simulation studies and ranked with respect to their over-all effect on the conversion of glycogen to cellulose and trehalose in the later stages of differentiation. Their order is, in decreasing effectiveness, (a) glycogen phosphorylase, (b and c) cellulose and trehalose synthetase, (d) UDP-glucose pyrophosphorylase and (e) glycogen synthetase. Glycogen phosphorylase controls the speed of differentiation, which can also be slightly modified by the level of glycogen synthetase. The cellulose and trehalose synthetases and UDP-glucose pyrophosphorylase control the relative concentrations of trehalose and cellulose. The final trehalose to cellulose ratio is also affected by the speed of differentiation. Compensatory interaction between enzymes affecting the outcome of differentiation is also analyzed.