What are the two methods of acetylcholine hydrolysis?

What are the two methods of acetylcholine hydrolysis?

• A. Enzymatic hydrolysis
• B. Acid catalyzed hydrolysis
• C. Base catalyzed hydrolysis
• D. Acid and base catalyzed hydrolysis

Answer: (D)

Two chemical paths describe acetylcholine hydrolysis: acid-catalyzed and base-catalyzed hydrolysis. In acid-catalyzed hydrolysis, protonation of the ester carbonyl makes the carbon more electrophilic, so water can attack, forming a tetrahedral intermediate that collapses to yield choline and acetate (or acetic acid after proton transfers). In base-catalyzed hydrolysis, hydroxide ion directly attacks the carbonyl carbon, again forming a tetrahedral intermediate that breaks down to the same products. These two pathways are distinct ways water can cleave the ester bond depending on the pH. In physiological conditions, enzymatic hydrolysis by acetylcholinesterase is the primary route, but non-enzymatic acid- and base-catalyzed hydrolysis represent the two chemical mechanisms of cleavage.

Two chemical paths describe acetylcholine hydrolysis: acid-catalyzed and base-catalyzed hydrolysis. In acid-catalyzed hydrolysis, protonation of the ester carbonyl makes the carbon more electrophilic, so water can attack, forming a tetrahedral intermediate that collapses to yield choline and acetate (or acetic acid after proton transfers). In base-catalyzed hydrolysis, hydroxide ion directly attacks the carbonyl carbon, again forming a tetrahedral intermediate that breaks down to the same products. These two pathways are distinct ways water can cleave the ester bond depending on the pH. In physiological conditions, enzymatic hydrolysis by acetylcholinesterase is the primary route, but non-enzymatic acid- and base-catalyzed hydrolysis represent the two chemical mechanisms of cleavage.