Enzyme inhibitors

Question 1

What is a competitive inhibitor?

Answer 1

A substance/molecule which is complementary in shape with the actie site of an enzyme and competes with the susbtrate molecule to bind with the active site

When the inhibitor binds an enzyme-inhibitor complex is formed. This stops the substrate from binding to the active site and prevents the enzyme from catalysing the reaction

Question 2

What is an emzyme inhibitor?

Answer 2

A substance or molecule which slows down/stops an enzyme controlled reaction

Question 3

What makes competetive enzyme inhibition reversible?

Answer 3

When a competetive inhibtior binds to th active site temporarily then its actions are reversible and have no permanent effect on the enzyme.

Question 4

What can you do to overcome the actions of a competetive inhibitor

Answer 4

When a competetive inhibitor binds temporarily to an active site, its actions are reversible and have no permanent effect on the enzyme.

To overcome the actions of the competetive inhibitor you increase the concentration of susbtrate molecules.

This increases the number of substrate molecules per unit volume which increases the frequecny of successful collisions between the active site and the substrate molecule rather than with the inhibitor. And so the rate of the reaction increases

Question 5

When would the effects of a competetive inhibitor not be reversible?

Answer 5

When the inhibitor binds permanently to the active site of the enzyme.

Increasing substrate concentration will not have an effect on the rate of the reaction

Question 6

How do non-competetive inhibitors work?

Answer 6

1. Non-competetive inhibitors bind to an allosteric site.
2. This causes the tertiary structure of the enzyme to change which changes the shape of the active site
3. Now, the ative site’s shape is no longer complementary to the substrate molecule and so enzyme-substrate complexes do not form

Question 7

Are non-competetive inhibitors reversible or irriversible?

Answer 7

Irriversible?

Question 8

Why are non-competetive inhibitor’s actions irriversible

Answer 8

They bind permanently to the allosteric site of the enzyme.

Question 9

Are the effects of a non-competitive inhibitor affected by substrate concentration?

Answer 9

No- as their actions are irreversible

Question 10

What determines the level of inhibition in terms of non-competitve inhibitors?

Answer 10

The number of non-competitive inhibitors present

as the substrate conc. doesnt affect it bc/ these inhibtors are permanent