enzyme inhibitors

Question 1

what are the 3 types of enzyme inhibitors

Answer 1

1) competitive (active site directive)
2) non competitive (not active site directed)
3) end product inhibition (type of non competitive)

Question 2

whats an enzyme inhibitor

Answer 2

-substances that reduce the activity of an enzyme
-bind to the enzyme and influence how the enzyme can work
-inhibit formulation of enzyme-substrate complexes and reduce the product formation
-can be permanent or temporary

Question 3

what does inhibitors reversible/irreversibility

Answer 3

-depending on whether their inhibitory effect on the enzyme is permanent or not

Question 4

examples of competitive inhibition

Answer 4

-aspirin and NSAID
-inhibit cyclooxygenase which produces prostaglandins (reduce inflammatory effect)

Question 5

how do competitive inhibitors work

Answer 5

-competitive inhibitor fits into the active and so a substrate molecule cannot enter

Question 6

what does the amount of inhibition of competitive inhibitors depend on

Answer 6

-the relative concentration of substrate and inhibitor molecules
-more inhibitor molecules means more inhibitors collide with active site so effect of inhibition is greater

Question 7

why do competitive inhibitors slow down rate of reaction with increasing substrate concentration, but it still increases

Answer 7

-if enough substrate is added, inhibitor is unlikely to collide with the enzyme
-increasing substrate concentration “dilutes” effect of inhibitor

Question 8

how do non-competitive inhibitors work

Answer 8

-binds to enzyme not at the active site
-binding of inhibitor changes shape of the active site
-enzyme substrate complex cannot form

Question 9

why does the graph of non competitive inhibitors not reach the same rate of reaction as others

Answer 9

-enzyme molecule has inhibitor bound to it so cannot catalyse reaction
-increasing conc has no effect on inhibitors ability to reduce enzymes rate of reaction
-max rate of reaction is controlled by the number of inhibitor molecules present

Question 10

how does end product inhibition work

Answer 10

-non competitively
-the final product often acts as a regulator of the pathway

Question 11

how does the product of an end product inhibition work to regulate a metabolic pathway

Answer 11

-when the amount of end product is high it binds non competitively to an enzyme in the pathway
-blocking further production of itself
-when amt of end product falls, inhibition ends and pathway restarts so activity increases again