A drug that compete for active binding site is called:
**Core Concept**
The concept being tested is the mechanism of drug action, specifically the interaction between a drug and its receptor. **Competitive inhibition** is a type of enzyme inhibition where a molecule binds to the active site of an enzyme, preventing the substrate from binding and thus inhibiting the enzyme's action.
**Why the Correct Answer is Right**
A competitive inhibitor competes with the substrate for binding to the active site of an enzyme. This means that the inhibitor and the substrate cannot occupy the active site simultaneously, and the presence of the inhibitor reduces the enzyme's activity by decreasing the availability of the active site for the substrate. This type of inhibition is reversible, meaning that the enzyme can regain its activity once the inhibitor is removed.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it refers to a type of non-competitive inhibition, where the inhibitor binds to a site other than the active site and alters the enzyme's shape, reducing its activity.
**Option B:** This option is incorrect because it refers to a type of irreversible inhibition, where the inhibitor covalently binds to the enzyme, permanently inactivating it.
**Option C:** This option is incorrect because it refers to a type of allosteric inhibition, where the inhibitor binds to a site other than the active site and alters the enzyme's activity without competing with the substrate for the active site.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that competitive inhibitors can be overcome by increasing the concentration of the substrate, allowing more substrate to bind to the active site and outcompete the inhibitor.
**Correct Answer: C. Allosteric inhibition is not the correct answer, however, the question is asking for the term for a drug that competes with the substrate for the active site of an enzyme. The correct answer is not listed, but the closest correct term is a "Competitive Inhibitor".**