REGULATION OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE OF DIFFERENT BACTERIAL SPECIES BY ATP

From cell free extracts of Hydrogenomonas facilis, Pseudomonas fluorescens, Escherichia coli, Acetobacter xylinum and A. suboxydans the glucose-6-phosphate dehydrogenases have been purified up to twenty or eighty fold. The enzymes from Hydrogenomonas and Pseudomonas are characterized by specificity for NAD and NADP, by sigmoid substrate (G-6-P)1 saturation curves, and by inhibition by adenosine triphosphate. The E. coli enzyme is specific for NADP and is not inhibited by ATP; the substrate saturation curves are hyperbolic even in the presence of ATP. The enzymes from Acetobacter xylinum and A. suboxydans exhibit specificity for NAD and NADP and hyperbolic substrate saturation curves and are not inhibited by ATP. The results coincide with the idea, the glucose-6-phosphate dehydrogenases functioning only in a degradative pathway are subject to adenylate control with ATP as a negative allosteric effector. © 1969 Springer-Verlag.