Question

What enzyme catalyzes breakdown of catecholamines in the synaptic cleft and in the mitochondria of the axon terminal of the presynaptic cell ______.

A) choline acetyl transferase
B) catechol-O-methyltransferase
C) acetylcholinesterase
D) monoamine oxidase
E) adenylate cyclase

Answer 1

Monoamine oxidase is the enzyme responsible for the breakdown of catecholamines in the synaptic cleft and the mitochondria of the axon terminal of the presynaptic cell.

Step-by-step explanation:

The enzyme that catalyzes the breakdown of catecholamines in the synaptic cleft and in the mitochondria of the axon terminal of the presynaptic cell is monoamine oxidase (Option D). Catecholamines, which include neurotransmitters such as dopamine, norepinephrine, and epinephrine, are broken down by monoamine oxidase to ensure that they do not continue to affect the postsynaptic cell after their signal has been transmitted.

This enzymatic activity is essential for maintaining proper neurological function and preventing overstimulation of the nervous system.

Answer 2

Monoamine oxidase is the enzyme that degrades catecholamines in the synaptic cleft and the axon terminal mitochondria, ensuring neurotransmitter levels are regulated properly. D is the correct answer.

Step-by-step explanation:

The enzyme that catalyzes the breakdown of catecholamines in the synaptic cleft and in the mitochondria of the axon terminal of the presynaptic cell is monoamine oxidase (D).

While acetylcholinesterase (AChE) is responsible for breaking down acetylcholine (ACh) into acetyl and choline in the synaptic cleft, monoamine oxidase is the enzyme involved in the degradation of catecholamines like norepinephrine and dopamine.

It prevents catecholamines from remaining active in the synaptic cleft, thus regulating neurotransmission and preventing prolonged effects.