1.9 - Enzyme inhibition

Question 1

Measuring enzymatic action through the breakdown of the substrate (starch to maltose using amylase)

Answer 1

1. enzyme amylase catalyses the breakdown of starch to maltose
2. add a drop of iodine into each spotting tile
3. a known conc of amylase and starch is mixed together in a test tube
4. a dropping pipette is used to put a drop into the wells
5. at regular intervals, colour is observed
6. the solution goes blue-black and record the time it takes to no longer turn blue black
7. repeat using diff conc. of amylase

Question 2

using hydrogen peroxide to produce oxygen within catalase enzyme

Formation of product experiment

Answer 2

1. set up the boiling tubes containing the same volume and conc. of hydrogen peroxide (keep pH constant by adding a suitable buffer solution)
2. set up this:
3. put each boiling tube in a water bath with diff. temps with another tube containing catalase
4. add some vol. and conc. of catalase to each boiling tube - attach the bung and delivery tube
5. record the O2 produced in the first minute - use a stopwatch to measure the time
6. repeat the experiment and find averages
7. calculate the average RoR

Question 3

What do non-competitive inhibitors do?

Answer 3

• attach themselves to the binding site (not the AS) (allosteric site)
• allows the shape of the enzyme and its AS so that the substrate molecules can no longer occupy it (no longer function)
• increase in substrate conc. doens’t affect the inhibitor

Question 4

How is enzyme activity affected by the difference between the conc. of the inhibitor and substrate? (Competitive)

Answer 4

• if substrate conc. increases - effect of the inhibitor decreases
• the inhibitor isn’t permanently bound to the AS so another molecule can take its place - depends on how much of each type is present
• all substrate molecules will occupy an AS later
• greater the conc of the inhibitor, longer it takes

Question 5

Competitive Inhibitors function:

Answer 5

• have a similar 3D shape to the substrate
• allows them to occupy the AS of an enzyme
• competes with the susbtrate for the available ASs

Question 6

What are enzyme inhibitors?

Answer 6

Substances that directly interfere with the functioning of the AS of an enzyme
reduces its activity