Enzyme inhibitors pt 2

Question 1

How does a non-competitive inhibition work?

Answer 1

1. inhibitors binds to the enzyme at a location other than the active site, this alternative site is called an allosteric site
2. The binding of the inhibitor causes the tertiary structure of the enzyme to change, meaning the active site changes shape
3. this results in the active site no longer having a complementary shape to the substrate so it is unable to bind to the enzyme
   
   1. the enzyme cannot carry out its function and it is said to be inhibited
      2.

Question 2

What effect does a non-competitve inhibitor have on the rates of reaction?

Answer 2

increasing the concentaration of enzymes or substrate will not overcome the effect of a non-competitve inhibitor

increasing the concentration of inhibitor, however, will decrease the reaction further as more active sites becomes unavailable

Question 3

What are irreversible inhibitors usually?

Answer 3

toxic

Question 4

What is organophosphates?

Answer 4

used as insecticides and herbicides irreversibly inhibt the enzymes acetyl chloibesterase, an enzymes necessary for nerve impulse transmission

leasds to cramps, paralysis and even death if accidently ingested

Question 5

What are proton pump inhibitors?

Answer 5

used to treat long-term indigestion

they irreversibly block an enzyme system responsible for secreting hydrogen ions into the stomach

this makes PPIs very effective in reducing the production of excess acid which, left untreated can lead to formation of stomach ulcers

Question 6

What is end-product inhibition?

Answer 6

the term used for enzyme inhibition that occurs when the product of a reaction acts as an inhibtor to the enzyme that produces it

this serves as a negative-feedback control mechanism for the reaction

Question 7

Why is end -product inhibition important?

Answer 7

excess products are not made and resources are not wasted

Question 8

Where does end-product inhibition occur in the body?

Answer 8

the addition of the second phosphate group to glucose, is catalysed by the enzyme phophofructokinase, this enzyme is competitively inhibited by ATP

therefore ATP regulates its own production

Question 9

WHat happens when ATP levels are high?

Answer 9

more ATP bind to the allosteric site of phosphofructikinase, preventing the additon of the second phosphate group to glucose

glucose is not broken down and ATP is not produced at the same rate

Question 10

What happens as ATP is used up?

Answer 10

less binds to phosphofructokinase and the enzyme is able to catalyse the addition of a second phosphate group to glucose

respiration resumes, leading to the production of more ATP

Question 11

Why is end-product inhibition more likely to be competivie than non-competitive?

Answer 11

concentrations o fsubstrate and product determine rate of reaction

so must be competitive

substrate concentration has no effect in non-competitive inhibition