**Question:** Not a feature of competitive inhibition?

A. Allosteric inhibition
B. Non-competitive inhibition
C. Uncompetitive inhibition
D. Non-specific inhibition

**Core Concept:**
Competitive inhibition is a type of enzyme inhibition where the inhibitor competes with the substrate for binding to the active site of the enzyme. This type of inhibition is reversible and specific, meaning the inhibitor only affects the substrate of interest and not other substrates or co-substrates.

**Why the Correct Answer is Right:**
Competitive inhibition involves the inhibitor competing with the substrate for binding to the active site of the enzyme. This is a specific type of inhibition, meaning it affects only the substrate of interest and not other substrates or co-substrates. Additionally, competitive inhibition is reversible, allowing the enzyme to regain its normal function when the inhibitor is removed.

**Why Each Wrong Option is Incorrect:**

A. Allosteric inhibition (A) is a type of enzyme inhibition where the inhibitor binds to a site other than the active site, such as the allosteric site. This type of inhibition affects the enzyme's conformation and activity, but not the substrate binding.

B. Non-competitive inhibition (B) is a type of enzyme inhibition where the inhibitor binds to a site other than the active site, causing a conformational change in the enzyme that reduces its catalytic activity. In contrast to competitive inhibition, non-competitive inhibition does not affect substrate binding.

C. Uncompetitive inhibition (C) is a type of enzyme inhibition where the inhibitor binds to the enzyme-substrate complex, reducing the enzyme's catalytic activity but not affecting substrate binding. This type of inhibition is different from competitive inhibition, where the inhibitor competes with the substrate for binding to the active site.

D. Non-specific inhibition (D) refers to the inhibition of an enzyme by an inhibitor that does not have a specific interaction with the enzyme. In the context of the question, competitive inhibition is specific, affecting substrate binding, while non-specific inhibition would affect the enzyme's activity without affecting substrate binding.

**Clinical Pearl:**
Understanding the difference between competitive inhibition and non-specific inhibition is crucial for understanding enzyme kinetics and drug interactions. Competitive inhibitors are specific to the substrate and can be overcome by increasing the substrate concentration, while non-specific inhibitors affect the enzyme globally and cannot be overcome by this strategy.