Which of the following drug binds only with the anionic site of cholinesterase
**Core Concept**
The anionic site of cholinesterase plays a crucial role in the enzyme's activity, and certain drugs specifically target this site to inhibit enzyme function. The anionic site is responsible for binding to the positively charged quaternary ammonium group of acetylcholine, facilitating the enzyme's catalytic activity.
**Why the Correct Answer is Right**
The correct answer binds specifically to the anionic site of cholinesterase, preventing the enzyme from interacting with acetylcholine. This is distinct from other inhibitors that bind to the peripheral or active site of cholinesterase. By binding to the anionic site, the correct answer effectively blocks the enzyme's ability to hydrolyze acetylcholine, leading to an accumulation of acetylcholine in the synaptic cleft.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a competitive inhibitor that binds to the active site of cholinesterase, not the anionic site.
**Option B:** This option is incorrect because it is a reversible inhibitor that binds to the peripheral site of cholinesterase, not the anionic site.
**Option C:** This option is incorrect because it is an irreversible inhibitor that covalently binds to the active site of cholinesterase, not the anionic site.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the anionic site of cholinesterase is a unique binding site that can be targeted by specific inhibitors, such as the correct answer. This knowledge can be useful in understanding the mechanism of action of various cholinesterase inhibitors used in the treatment of Alzheimer's disease and other neurological disorders.
**Correct Answer: C. Edrophonium**