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Enzyme Inhibitors Task
Non- Competitive Inhibitors
Non- competitive inhibitors do not resemble the substrate in inhibition. It binds with the enzyme molecule at a place other than its active site.
It can be reversible or irreversible inhibition depending on whether the inhibitor bonds briefly or permanently with the enzyme.
A non-competitive inhibitor will reduce the rate of a reaction by reducing the activity of the enzyme. The inhibitor binds to a site on the enzyme that is not the active site.
Digitalis (a substance extracted from fox glove) is an example of a non- competitive inhibitor. It binds with the enzyme ATPase, resulting in an increase in contractions of the heart.
Competitive Inhibitors
A competitive enzyme inhibitor has a similar shape to the substrate molecule. This causes it to compete with the substrate for the enzymes active site.
Competitive inhibitors are reversible because they can be undone by increasing the concentration of the substrate. However they sometimes can remain bonded to the active site.
They fit into the Active Site, but remain unreacted since they have a different structure to the substrate. Therefore less substrate molecules can bind to the enzymes so the reaction rate is decreased.
Example: Ethanol is metabolized in the body by oxidation to acetaldehyde, which is in turn further oxidized to acetic acid by aldehyde oxidase enzymes. Normally, the second reaction is rapid so that acetaldehyde does not accumulate in the body.
This graph shows how inhibitors affect rate of reaction.

Inhibitor Questions
Is a competitive inhibitor more like an enzyme substrate than a non- competitive inhibitor? Explain why?
Describe how a non- competitive inhibitor, a competitive inhibitor and a normal enzyme will place on a graph.
Describe a competitive inhibitors relation with an enzyme in comparison with a non- competitive inhibitors relation with an enzyme.