2nd +P of F6P by PFK1

Question 1

What enzyme is involved with 2nd Pi of F6P

Answer 1

Phosphofructokinase-1 (PFK-1)

Question 2

PFK1 mechanism is similar to

Answer 2

hexokinase, is SN2-like.

Question 3

Why does it matter that PFK1 has several isoforms present and found in various tissues?

Answer 3

different tissues have difff functions, so they regulate differently

Question 4

Why is phosphorylation of F6p by PFK1 a key regulation point?

Answer 4

HK brings gluc into the cell, marks the gluc. Once G6P, can do glycolysis, Pentose Phosphate Pathway, glycogen production. HK is NOT unique to glycolysis.

So this is important because this is the last ATP investment before glycolysis, so it is specific to glycolysis.

Question 5

key inhibitors of PFK1

Answer 5

• high [ATP]
  high important bc ATP is also a substrate.
  High atp tells you the cell has sufficient levels of ATP, dont need to make more, known as the fed state
• citrate
  citrate is product of first rxn of citric acid cycle.
  If a lot of citrate, it means citric acid cycle inhibited. If citric acid cycle inhibited, fewer enzymes doing it, which means there is a lot of energy, so dont need more, long range feedback

Question 6

How does F6P regulate by substrate availability

Answer 6

• if F6P is available, it will be used by PFK1. if not available, PFK1 cannot use

Question 7

key activators and de-inhibitors of PFK1

Answer 7

ACTIVATORS:
- ADP, AMP (low E, in fast state, need more E)

DE-INHIBITORS:
- F2,6P