Glycolysis

• Glycolysis

  • Converts Glucose to 3C compounds to provide energy (Embden-Meyerhof-Parnas)
  • Site : Cytosol of All Cell 
  • Substrate : Glucose
  • Products : Pyruvate, NADH, ATP
  • RLE : Phosphofructokinase
• Step 1. Formation of Glucose-6-Phosphate

  • Reaction: Phosphorylation using ATP
  • Enzyme: Hexokinase
  • ATP is invested - ℗ from ATP is added to C6
• Step 2. Formation of Fructose-6-Phosphate

  • Reaction: Isomerization
  • Enzyme: Phosphoglucoisomerase
  • G-6-℗ is rearranged from a 6-membered ring into a 5-membered ring; C1 is no longer part of the ring structure
• Step 3. Formation of Fructose-1,6-Bisphosphate

  • Reaction: Phosphorylation using ATP
  • Enzyme: Phosphofructokinase RATE-LIMITING ENZYME
  • ATP is invested - ℗ is added to C1
• Step 4. Formation of Triose Phosphates

  • Reaction: Cleavage (Lyase) 
  • Enzyme: Aldolase
  • Fructose-1,6-Bis℗ (C6) is cleaved into two 3 carbon molecules
• Step 5. Isomerization of Triose Phosphates

  • Reaction: Isomerization 
  • Enzyme: Triosephosphate isomerase
  • DHA℗ is rearranged to form Glyceraldehyde-3-℗
• Step 6. Formation of 1,3-Bisphosphoglycerate

  • Reaction: Oxidation & Phosphorylation 
  • Enzyme: Glyceraldehyde 3-phosphate dehydrogenase
  • ℗i added to C3 of Glyceraldehyde-3-℗
  • Hydrogen of Aldehyde group binds with NAD+ to form NADH
• Step 7. Formation of 3-Phosphoglycerate

  • Reaction: Substrate-level Phosphorylation 
  • Enzyme: Phosphoglycerokinase
  • ℗ removed from C1 is transferred to an ADP molecule, forming ATP
  • substrate-level phosphorylation
• Step 8. Formation of 2-Phosphoglycerate

  • Reaction: Isomerization 
  • Enzyme: Phosphoglyceromutase
  • ℗ is moved from C3 to C2
• Step 9. Formation of Phosphoenolpyruvate

  • Reaction: Dehydration 
  • Enzyme: Enolase
  • Alcohol dehydration produces a –C=C– bond
• Step 10. Formation of Pyruvate

  • Reaction: Substrate-level Phosphorylation 
  • Enzyme: Pyruvate Kinase
  • ℗ removed from C2 is transferred to an ADP molecule, forming ATP
  • substrate-level phosphorylation
• Control Points of Glycolysis (Feedback Inhibition)

  • Step 1 : HEXOKINASE
  • glucose → glucose-6-phosphate inhibited by: glucose-6-phosphate 
  • Step 3 : PHOSPHOFRUCTOKINASE
  • fructose-6-phosphate → fructose-1,6-bisphosphate inhibited by: citrate, ATP
  • Step 10 : PYRUVATE KINASE
  • phosphoenolpyruvate → pyruvate (pyruvate kinase) inhibited by: ATP