Lecture 13

Question 1

What is an enzyme inhibitor?

Inhibition can be _________ or ________

Answer 1

Is a compound that binds to an enzyme and reduces its activity

Inhibition can be reversible or irreversible

Question 2

What are irreversible inhibitors?

Answer 2

Are bound by covalent bonds ; this forms a permanent bond between - CANNOT be undone

Question 3

What are reversible inhibitors?

What are the two types of reversible inhibitors?

Answer 3

Are bound by non-covalent bonds - therefore the formation of the EI, enzyme inhibitor complex IS REVERSIBLE

= competitive and non-competive inhibitors

Question 4

What are competitive inhibitors ?

Answer 4

• They bind to active site of the enzyme, denying the substrate
  = compete with the substrate for the active site of an enzyme and prevents binding of the substrate
• competitive inhibitors combine with enzyme to form an EI complex
• DOES not change the enzyme

Question 5

How to competitive inhibitors effect

• KM
• Vmax

Answer 5

Competitive inhibitor competes for active site so:
- KM will increase = lower affinity

• Vmax = NO change

Question 6

What are non-competitive inhibitors?

Answer 6

• They bind to another spot on the enzyme - DO NOT bind to the active site therefore do NOT affect KM
• The enzyme does not work when the inhibitor is bound; it lower the enzyme concentration and therefore enzyme cannot worked at maximum speed

Question 7

How do non-competitive inhibitors effect

• KM
• Vmax

Answer 7

KM does not change - as it does not bind to active site so affinity for substrate does not change
Vmax - decreases as bound inhibitor changes enzyme shape it cannot function properly - CANNOT work at maximum speed