Question

How can competitive and noncompetitive inhibition be distinguished in terms of KM?

a. The apparent value of KM decreases with a competitive inhibitor, while it remains unchanged with a noncompetitive inhibitor.
b. The apparent value of KM increases with a competitive inhibitor, while it decreases with a noncompetitive inhibitor.
c. The apparent value of KM increases with a competitive inhibitor, while it remains unchanged with a noncompetitive inhibitor.
d. The apparent value of KM remains unchanged with a competitive inhibitor, while it increases for a noncompetitive inhibitor.

Answer 1

The correct answer is option c. "The apparent value of KM increases with a competitive inhibitor, while it remains unchanged with a noncompetitive inhibitor".

Step-by-step explanation:

The KM value in an enzymatic reaction is defined as the substrate concentration at which the half of the enzyme molecules are binding with the substrate. A way to distinguish between a competitive and noncompetitive inhibition is that the apparent value of KM increases with a competitive inhibitor, while it remains unchanged with a noncompetitive inhibitor. A competitive inhibitor would make that a higher concentration of substrate is needed, while a noncompetitive inhibitor does not change KM since the inhibitor binds to a site of the enzyme different from the active site.