Bass liver 6-phosphogluconate dehydrogenase: inhibition by nucleoside phosphates and by fructose 1,6 bisphosphate

Nucleoside 5'-triphosphates, 5'-diphosphates and 5'-monophosphates are inhibitors of the 6-phosphogluconate dehydrogenase enzyme from bass liver. The 2'- and 3'-monophosphates of adenosine and guanosine are also inhibitory, the 2'-isomers being especially potent inhibitors. The catalytic activity of 6-phosphogluconate dehydrogenase has been found to be markedly inhibited by fructose 1, 6 bisphosphate. As the Km for 6-phosphogluconate, the Ki for fructose 1,6 bisphosphate and the concentration of both compounds in bass liver are all comparable, it appears that the inhibition of 6-phosphogluconate dehydrogenase by fructose 1,6 bisphosphate may be of significance in the regulation of carbohydrate metabolism in bass liver.