Phosphofructokinase: Step 3 of Glycolysis

Question 1

Why reaction is catalyzed by phosphofructokinase?

Answer 1

The phosphorylation of fructose 6-kinase to form fructose-1, 6-bisphosphate.

Question 2

Why is fructose-1,6-bisphosphate a “bis” rather than “bi” product?

Answer 2

Because the two phosphates are not directly attached to each other.

Question 3

How is phosphofructokinase (PFK) similar to hexokinase?

Answer 3

It requires ATP and Mg2+ to phosphorylate its substrate.

Question 4

What is the key regulatory enzyme for glycolysis?

Answer 4

Phosphofructokinase (PFK)

Question 5

True or false: The reaction from fructose-6-phosphate (F6P) to fructose-1,6-bisphosphate (FBP) is reversible?

Answer 5

False

Question 6

What molecule allosterically enhances the activity of PFK?

Answer 6

AMP

Question 7

What allosterically inhibits PFK?

Answer 7

ATP and citrate

Question 8

What enzyme catalyzes the reaction from F6P to FBP?

Answer 8

Phosphofructokinase

Question 9

Why does AMP enhance the activity of PFK?

Answer 9

ATP breaks down into ADP and AMP, so high concentrations of AMP signal that ATP concentration is low.