Test 2 Glucose and Fructose Metabolism

Question 1

Regulating steps of Glycolysis

Answer 1

• Formation of Fructose-1,6-bisphosphate by phosphofructokinase-1 is regulated step.
  
  • High amounts of ATP inhibits this reaction
  • High amounts of citrate inhibit this reaction, since it indicates that the citric acid cycle is going fine.
  • High amounts of AMP and ADP stimulate this reaction.

Question 2

What is the key regulatory enzyme for glycolysis? and what was learned about it.

Answer 2

• Pyruvate Kinase
  
  • High energy charge greatly inhibits enzyme activity
  • Fructose-1,6-Bisphosphate activates enzyme
  • In the liver, it is regulated by cyclic AMP-dependent protein kinase phosphorylation.
    
    • Phosphorylated = less active
    • Dephosphorylated = more active