Which two cholinesterases are present in humans?

Which two cholinesterases are present in humans?

• A. Acetylcholinesterase (AChE) and Butyrylcholinesterase (BuChE)
• B. Acetylcholinesterase (AChE) and Choline acetyltransferase
• C. Butyrylcholinesterase (BuChE) and Choline esterase
• D. Cholinesterase family present in animals only

Answer: (A)

The basic idea is identifying the two cholinesterases present in humans. Acetylcholinesterase (AChE) is the primary enzyme at cholinergic synapses and neuromuscular junctions, quickly hydrolyzing acetylcholine to terminate signaling. Butyrylcholinesterase (BuChE), also known as pseudocholinesterase, is found mainly in plasma and has broader substrate specificity, acting on various choline esters including butyrylcholine; it can also help detoxify certain esters and can act as a scavenger for organophosphates. The other options mix in an enzyme that synthesizes acetylcholine (not a cholinesterase), refer to a nonstandard “choline esterase,” or incorrectly claim this family is present only in animals. So the correct pairing is acetylcholinesterase and butyrylcholinesterase.

The basic idea is identifying the two cholinesterases present in humans. Acetylcholinesterase (AChE) is the primary enzyme at cholinergic synapses and neuromuscular junctions, quickly hydrolyzing acetylcholine to terminate signaling. Butyrylcholinesterase (BuChE), also known as pseudocholinesterase, is found mainly in plasma and has broader substrate specificity, acting on various choline esters including butyrylcholine; it can also help detoxify certain esters and can act as a scavenger for organophosphates. The other options mix in an enzyme that synthesizes acetylcholine (not a cholinesterase), refer to a nonstandard “choline esterase,” or incorrectly claim this family is present only in animals. So the correct pairing is acetylcholinesterase and butyrylcholinesterase.