6-Phosphogluconic acid

6-Phosphogluconic acid is a potent and competitive inhibitor of phosphoglucose isomerase (PGI) .The activity of phosphoglucose isomerase was inhibited intensely and competitively by 6-Phosphogluconic acid, with an apparent Ki of 0.048 mM for glucose 6-phosphate and 0.042 mM for fructose 6-phosphate as the substrate. (In Vitro) :With glucose 6-phosphate as the substrate, at concentrations from 0.05 to 0.5 mM, the activity of the enzyme was inhibited completely in the presence of 0.5-2.0 mM 6-Phosphogluconic acid. With 0.05-0.2 mM fructose 6-phosphate as the substrate, it was inhibited greater than or equal to 85% at the same concentrations of the inhibitor. No significant changes were observed in the values of Km, Vmax, and Ki for phosphoglucose isomerase in the brain of 6-aminonicotinamide-treated rats.