Entner-Doudoroff (ED) pathway




Entner-Doudoroff (ED) pathway

  • This pathway occurs in both aerobic and anaerobic condition
  • Occur in prokaryotes only
  • It occurs in cytoplasm
  • Pyruvate and glyceraldehyde-3-phosphate produced from glucose by ED pathway

  • At first glucose is phosphorylated to glucose -6-phosphate by the enzyme hexokinase.
  • Glucose-6-phosphate is then oxidized to 6-phosphogluconolactone releasing a molecule of NADPH. This reaction is catalyzed by the enzyme glucose-6-phosphate dehydrogenase.
  • Hydrolase enzyme converts 6-phopshogluconolactone to 6-phosphogluconate.
  • 6-phosphogluconate undergoes dehydration reaction catalyzed by 6-phosphogluconate dehydratase to form 2-keto 3-deoxy 6-Phosphogluconate (KDPG).
  • KDPG splits to form pyruvate and glceraldehyde-3-phosphate. It is catalyzed by KDPG aldolase enzyme
  • Glyceraldehyde-3-phosphate is then metabolized by glycolysis to form pyruvate.

 

Significance of ED pathway

  • This pathway used two specific enzymes ie. 6-phosphogluconate dehydratase and KDPG aldolase.
  • This pathway generates 1 ATP, 1 NADH and 1 NADPH from one glucose molecule.

Entner-Doudoroff (ED) pathway