Session 11: Regulation of Protein Function

Question 1

What are isoenzymes?

Answer 1

Different forms of the same enzyme with different kinetic properties,

Question 2

What is product inhibition?

Answer 2

When accumulation of the product of a reaction inhibits the forward reaction.

Question 3

TRUE OR FALSE: allosteric enzymes show a sigmoidal relationship between rate and substrate concentration.

Answer 3

TRUE

Question 4

What graphical shape do simple enzymes show when charting the relationship between rate and substrate concentration.

Answer 4

Rectangular hyperbola

Question 5

What does an allosteric activator do?

Answer 5

Increase the proportion of the enzyme in the R state (high affinity state)

Question 6

What does an allosteric inhibitor do?

Answer 6

Increase the proportion of the enzyme in the T state (low affinity state)

Question 7

Name 2 allosteric activators of phosphofructokinease.

Answer 7

1. AMP

2. Fructose-2,6-bisohosphate

Question 8

Name 3 allosteric inhibitors of phosphofructokinease.

Answer 8

1. H+
2. Citrate
3. ATP

Question 9

What do protein kinases do?

Answer 9

Add a phosphate group

Question 10

What do protein phosphates do?

Answer 10

Remove a phosphate group

Question 11

TRUE OR FALSE : proteolytic cleavage is irreversible

Answer 11

TRUE

Question 12

Define zymogen

Answer 12

Inactive precursors

Question 13

Name 2 long term protein regulations.

Answer 13

1. Change in rate of protein synthesis

2. Change in rate of protein degradation