competitive inhibition


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


The Vmax with the inhibitor is the same as in the absence of inhibitor.

Compare this to the situation with the curve for noncompetitive inhibition

If the Vmax with the inhibitor is the same as in its absence, then the amount of active enzyme in the absence of inhibitor is the same as in its presence.

Thus the enzyme does not inactivate the enzyme, it only occupies it.

This could happen in the inhibitor bound to the active site but was not converted to product.

In the presence on inhibitor, there are two substances binding and competing for the active site: the substrate and the inhibitor.

The inhibitor has a shape sufficiently like the substrate so that it will bind to the active site but the inhibitor will not undergo catalysis


To know how much is inactive at that particular substrate concentration, go up to the rate curve at the top of the page and move the cursor around the curve. When the pointer turns to a finger click on the mouse to see how much enzyme is active and and how much is inactive



return to modulators of enzyme activity