Ribose 1,5-bisphosphate regulates rat kidney cortex phosphofructokinase

Phosphofructokinase (EC 2.7.1.11) is a major enzyme of the glycolytic pathw ay, catalyzing the conversion of fructose 6-phosphate to fructose 1,6-bisph osphate. In this study, we demonstrated the effect of ribose 1,5-bisphospha te on phosphofructokinase purified from rat kidney cortex. Ribose 1,5-bisph osphate relieved the phosphofructokinase from ATP inhibition and increased the affinity for fructose 6-phosphate at nanomolar concentrations. These ac tivating effects of ribose 1,5-bisphosphate were enhanced in the presence o f AMP. Ribose 1,5-bisphosphate reduced the inhibition of the phosphofructok inase induced by citrate. These results suggest that ribose 1,5-bisphosphat e is an activator of rat kidney cortex phosphofructokinase and synergistica lly regulates the enzyme activity with AMP. (C) 1999 Elsevier Science Inc. All rights reserved.