Noncompetitive Enzyme Inhibitors

When doing reactions with and without a suspected enzyme inhibitor (substance X) the results could look like the following

When one plots the results of these reactions the following results could be obtained

From the curves the following conclusions can be made

Substance X reduces the rate of the reaction and is therefore and inhibitor.

These curves tell us that the Vmax with substance X is lower than the Vmax without this substance.

This indicates that the amount of active enzyme when the inhibitor is present is lower than the amount of active enzyme present when the inhibitor is absent.

How could substance X inhibit the enzyme?

Substance X could bind to the enzyme at a site other than the active site.

When the inhibitor binds to the inhibitor bind site (also known as the allosteric site) the conformation of the enzyme could change so that the substrate can no longer bind to the active site of the enzyme and catalysis can no longer occur.

To find out how the presence of this inhibitor could affect the maximum velocity of the reaction move the cursor to the curve at the top of the page until a pointing finger appears

What kind of compound could this substance X be?

It could be a feedback inhibitor

return to outline

return to competitive inhibitor

return to modulators of enzyme activity