2.4.7 Enzyme Activity: Enzyme Inhibitors

Question 1

Reversible Inhibitors

Answer 1

An enzyme’s activity can be reduced or stopped, temporarily, by a reversible inhibitor
There are two types of reversible inhibitor
There are two types of reversible inhibitors:
- competitive inhibitors have a similar shape to that of the substrate molecules and therefore compete with the substrate for the active site
- non-competitive inhibitors bind to the enzyme at an alternative site, which alters the shape of the active site and therefore prevents the substrate from binding to it

Question 2

Reversible Inhibitors and Reaction Rate

Answer 2

Both types of reversible inhibitors slow down or stop enzyme activity, decreasing the rate of reaction
Increasing the concentration of an inhibitor, therefore, reduces the rat of reaction and eventually, if the inhibitor concentration continues to be increased, the reaction will stop completely
For competitive inhibitors, countering the increase inhibitor or concentration by increasing the substrate concentration can increase the rate of reaction once more (more substrate molecules means they are more likely to collide with the enzymes and from enzyme-substrate complexes)
For non-competitive inhibitors, increasing the substrate concentration cannot increase the rate of reaction once more, as the shape of the active site of the enzyme remains a hanged and the enzyme-substrate complexes are unable to form