Which modification contributes to Carbachol's longer half-life compared to acetylcholine?

Which modification contributes to Carbachol's longer half-life compared to acetylcholine?

• A. A Methyl Group On The Beta Carbon
• B. Adding A Hydroxyl Group To Increase Polarity
• C. Removing The Ester To Prevent Hydrolysis
• D. An Amine Substitution On The Acetyl Group

Answer: (D)

Extending half-life here comes from making the molecule more resistant to enzymatic breakdown by acetylcholinesterase. Acetylcholine is rapidly hydrolyzed because it has a simple acetyl ester. By substituting an amine onto the acetyl group, the ester is converted into a carbamate, which is much less susceptible to AChE hydrolysis. That increased metabolic stability lets the molecule stay active longer in the synapse. The other potential modifications wouldn’t provide the same resistance to hydrolysis or would disrupt the molecule’s activity in different ways.

Extending half-life here comes from making the molecule more resistant to enzymatic breakdown by acetylcholinesterase. Acetylcholine is rapidly hydrolyzed because it has a simple acetyl ester. By substituting an amine onto the acetyl group, the ester is converted into a carbamate, which is much less susceptible to AChE hydrolysis. That increased metabolic stability lets the molecule stay active longer in the synapse. The other potential modifications wouldn’t provide the same resistance to hydrolysis or would disrupt the molecule’s activity in different ways.