Question

Which of the following enzyme hydrolyses the acetylcholine?
A. Acetylcholine transferase
B. Acetylcholine esterase
C. Acetylcholine dehydrogenase
D. Sorbitol dehydrogenase
E. Monoamine oxidase
Choose the correct answer from the options given below:

• A. A and C only
• B. B only
• C. D and E only
• D. A, B and C only

Hint:

Cholinergic Enzymes:
Synthesis = Choline Acetyltransferase (ChAT).
Inactivation Hydrolysis = ACETYLCHOLINESTERASE (AChE).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Synaptic cholinergic neurotransmission termination: acetylcholinesterase rapidly hydrolyzes acetylcholine at cholinergic synapses into acetate and choline.
Key Formula or Approach:
\[ \text{Acetylcholine} + \text{H}_2\text{O} \xrightarrow{\text{Acetylcholinesterase (AChE)}} \text{Choline} + \text{Acetate} \]

Step 2: Detailed Explanation:
In autonomic and neuromuscular junction neuropharmacology:
- Acetylcholinesterase (AChE Acetylcholine esterase) is a high-speed serine hydrolase localized in the synaptic cleft and postsynaptic basement membrane.
- It terminates neurotransmitter action by hydrolyzing Acetylcholine (ACh) into free choline and acetic acid within microseconds ($k_{\text{cat}} \approx 2.5 \times 10^4\text{ s}^{-1}$).
- (Choline acetyltransferase synthesizes ACh; Monoamine oxidase metabolizes catecholamines/serotonin).
Therefore, the hydrolyzing enzyme is B only.

Step 3: Final Answer:
Hence, the enzyme that hydrolyzes acetylcholine is B only, corresponding to option (B).