Enzyme inhibitors

Question 1

AS level. C.3 Enzyme inhibitors

Answer 1

https://www.youtube.com/watch?v=8woEVmLWTbk

Question 2

How are enzymes activated?

Answer 2

With cofactors

Question 3

How are enzymes inactivated?

Answer 3

With inhibitors

Question 4

What are the two types of enzyme inhibitors?

Answer 4

Competitive and non-competitive

Question 5

Explain how competitive inhibitors inhibit an enzyme

Answer 5

A molecule which has the same or similar shape to the active site of the enzyme fits into the active site. This then blocks the substrate from entering the active site and prevents the reaction from happening.

Question 6

Are competitive inhibitors temporary?

Answer 6

Yes, they only bind to the active site of an enzyme for a short amount of time.

Question 7

What are the two examples of competitive inhibitors?

Answer 7

Statins and Aspirin

Question 8

What are statins used for?

Answer 8

They decrease synthesis of cholesterol and so lower the blood cholesterol levels

Question 9

What problems could high blood cholesterol levels cause?

Answer 9

Heart disease

Question 10

What is aspirin used for?

Answer 10

Irriversible inhibits the active site of COX enzymes, preventing the synthesis of prostaglandins and thromboxane

Question 11

What are the prostaglandins and thromboxane chemicals responsible for?

Answer 11

producing pain and fever

Question 12

Explain how non-competitive inhibitors inhibit an enzymes

Answer 12

It binds to the allosteric site on the enzyme. This causes the tertiary structure of the enzyme to change and so the shape of the active site changes.

Question 13

What enzyme can organophosphate inhibit?

Answer 13

acetyl cholinesterase

Question 14

What is organophosphate typically used for?

Answer 14

insecticides and herbicides

Question 15

What is the enzyme acetyl cholinesterase necessary for?

Answer 15

Nerve impulse transmissions

Question 16

What could happen if organophosphate inhibits the enzyme acetyl cholinesterase?

Answer 16

It could result in muscle cramps, paralysis and death (if ingested

Question 17

What does PPIs stand for?

Answer 17

Proton pump inhibitors

Question 18

What can be treated by PPIs?

Answer 18

Long-term indigestion

Question 19

How do PPIs treate long-term indigestion?

Answer 19

They erriversible inhibit an enzyme resposnible for secreting H+ ions into the stomach (stops the build up of excess acid)

Question 20

What is meant by the term end-product inhibition?

Answer 20

It is where an enzyme inhibition occurs when the product of a reaction acts an inhibitor to the enzyme that produces it.

Question 21

What is the result of end-product inhibition?

Answer 21

It means that their is negative-feedback control mechanism for the reaction

Question 22

Does the process of end-product inhibition use competitive or non-competitive inhibition?

Answer 22

Non-competitive reversible inhibition

Question 23

Glucose is broken down by adding two phosphate groups to the molecule. What is the name of the enzyme which catalyses the addition of the second phosphate group?

Answer 23

PFK

Question 24

What does PFK stand for?

Answer 24

Phosphofructokinase

Question 25

What is PFK conpetitively inhiited by?

Answer 25

ATP

Question 26

How does ATP regulate its own production?

Answer 26

If a large amount of ATP is produced then more of it will bind to the PFK enzyme. This will prevent more ATP being produced.