A cyclic AMP dependent protein kinase in Dictyostelium discoideum

A cyclic AMP-dependent protein kinase was found to appear during the time course of development of $\text{Dictyostelium}\text{discoideum}$. No cyclic AMP dependency was observed at any stage of development in crude 110,000 X G soluble extracts. After partial purification, however, extracts from post-aggregation stages contained enzyme that was activated up to 6-fold by cyclic AMP, whereas protein kinase from earlier stages was not affected by cyclic AMP. Likewise, cyclic AMP binding activity increased from the aggregation to the slug stage of development. Approximately one-half of the total cyclic AMP binding activity co-purified with the cyclic AMP dependent protein kinase. The enzyme from $\text{Dictyostelium}$ showed similarities to mammalian protein kinases with respect to its kinetic properties but differed in its behavior on ion-exchange chromatography.