Abstract
Isocitric dehydrogenase, glucose-6-phosphate dehydrogenase, glutamic dehydrogenase, and glutamic-pyruvic trans -aminase do not change in concentration during differentiation in Dictyostelium discoideum, in spite of alterations in the intensity of metabolic pathways probably involving changing activities of these enzymes in vivo. It is suggested that sequential substrate utilization (and inhibition) could account for some metabolic changes occurring during differentiation.