Pyrophosphate and Fructose 2,6-Bisphosphate Effects on Glycolysis in Pea Seed Extracts

Abstract

The participation of PPi-dependent phosphofructokinase (PPi-PFK) in plant glycolysis was examined using extracts from pea seeds. Glycolysis starting with fructose 6-phosphate was measured under aerobic conditions as the accumulation of pyruvate. Pyruvate accumulated in a medium containing PPi and ADP at .apprx. 2/3 of the rate in a medium containing ADB and ATP. The PPi-dependent pyruvate accumulation had the same reactant requirements and sensitivity to glycolysis inhibitors, sodium fluoride and iodoacetamide, as the well-established ATP-dependent glycolysis. Added fructose 2,6-bisphosphate stimulated both the PPi-dependent pyruvate accumulation and PPi-PFK activity whereas this modulator had no effect on ATP-dependent glycolysis or ATP-PFK. Collectively these results demonstrate a PPi-dependent glycolytic pathway in plants which is responsive to fructose 2,6-bisphosphate.