The key difference between acetylcholinesterase and butyrylcholinesterase is that acetylcholinesterase is the main cholinesterase prominently found in cholinergic synapses and red blood cell membrane while butyrylcholinesterase is a non-specific cholinesterase mainly found in the blood plasma.
Cholinesterase is an enzyme that helps the nervous system work properly. It catalyzes the hydrolysis or breaking of cholinergic neurotransmitters like acetylcholine into choline and acetic acid when after transmitting nerve signals. Certain toxic chemicals in the environment, such as organophosphates, can interfere with this enzyme and affect the nervous system. There are two main types of cholinesterase: acetylcholinesterase and butyrylcholinesterase.
CONTENTS
1. Overview and Key Difference
2. What is Acetylcholinesterase (AChE)
3. What is Butyrylcholinesterase (BChE or pseudocholinesterase (PCHE))
4. Similarities – Acetylcholinesterase and Butyrylcholinesterase
5. Acetylcholinesterase vs. Butyrylcholinesterase in Tabular Form
6. FAQ – Acetylcholinesterase and Butyrylcholinesterase
7. Summary – Acetylcholinesterase vs. Butyrylcholinesterase
What is Acetylcholinesterase (AChE)?
Acetylcholinesterase is the primary cholinesterase present in the body. It catalyzes the breaking down of acetylcholine and some other choline esters functioning as neurotransmitters. Acetylcholinesterase helps to terminate synaptic transmission. In 1968, Walo Leuzinger and co-workers were successful in the purification and crystallization of acetylcholinesterase from electric eels at Columbia University, New York. In 1991, Joel Sussman and coworkers determined the 3D structure of acetylcholinesterase using protein from the Pacific electric ray.
Figure 01: Acetylcholinesterase
Acetylcholinesterase is also known as AChE. It is mainly found in the blood on red blood cell membranes, in neuromuscular junctions, and in other neural synapses. Acetylcholinesterase can exist in different forms. In the mammalian brain, the majority of AChE occurs as a tetrameric, G4 form. Only smaller amounts of a monomeric or G1 form of acetylcholinesterase are found in the mammalian brain.
What is Butyrylcholinesterase?
Butyrylcholinesterase is also known as BChE or pseudocholinesterase (PCHE). It is normally present in serum, plasma, liver, pancreas, heart, and other tissues. The liver produces this plasma enzyme, and it is responsible for the metabolism of common anesthesia drugs, succinylcholine, mivacurium, and ester local anesthetics, including cocaine.
Figure 02: Butyrylcholinesterase
Moreover, individuals with normally functioning butyrylcholinesterase can rapidly metabolize succinylcholine and mivacurium. This leads to the short duration of action of the above drugs in the body. However, when there is a deficiency of this enzyme, the body is unable to metabolize succinylcholine and mivacurium to the same degree. This will result in a condition called pseudocholinesterase deficiency, characterized by prolonged neuromuscular paralysis.
What are the Similarities Between Acetylcholinesterase and Butyrylcholinesterase?
- Acetylcholinesterase and butyrylcholinesterase are two different types of Cholinesterases.
- Both types are hydrolytic enzymes.
- Both types are able to hydrolysis of choline-based esters.
- The organophosphates inhibit both.
- They are extremely important for nerve function
What is the Difference Between Acetylcholinesterase and Butyrylcholinesterase?
Acetylcholinesterase is the main cholinesterase prominently found in cholinergic synapses and red blood cells, while butyrylcholinesterase is a non-specific cholinesterase mainly found in the blood plasma. Thus, this is the key difference between acetylcholinesterase and butyrylcholinesterase. Furthermore, acetylcholinesterase is also known as AChE, AChase, or acetylhydrolase. On the other hand, butyrylcholinesterase is also known as BChE or pseudocholinesterase (PCHE).
The infographic below presents the difference between acetylcholinesterase and butyrylcholinesterase in tabular form for side-by-side comparison.
FAQ: Acetylcholinesterase and Butyrylcholinesterase
What are the two sites of acetylcholinesterase?
Anionic and esteratic sites are the two sites of acetylcholinesterase.
What causes low levels of butyrylcholinesterase?
Protein-energy malnutrition, during stress and (chronic and acute) inflammation, and in other clinical conditions are some of the causes of low levels of butyrylcholinesterase.
Which acetylcholinesterase inhibitor is best?
Donepezil and rivastigmine are the best cholinesterase inhibitors.
Summary – Acetylcholinesterase vs. Butyrylcholinesterase
The two major types of cholinesterase are acetylcholinesterase (true cholinesterase) and butyrylcholinesterase (pseudocholinesterase). Acetylcholinesterase is the main cholinesterase prominently found in cholinergic synapses and red blood cell membranes, while butyrylcholinesterase is a non-specific cholinesterase mainly found in the blood plasma. Furthermore, acetylcholinesterase is the main cholinesterase that catalyzes the hydrolysis of the neurotransmitter acetylcholine (ACh) into choline and acetic acid, whereas butyrylcholinesterase is a nonspecific cholinesterase that responsible for the metabolism of the common anesthesia drugs, succinylcholine, mivacurium and ester local anesthetics which including cocaine. So, this summarizes the difference between acetylcholinesterase and butyrylcholinesterase.
Reference:
1. K;, Greig NH;Lahiri DK;Sambamurti. “Butyrylcholinesterase: An Important New Target in Alzheimer’s Disease Therapy.” International Psychogeriatrics, U.S. National Library of Medicine.
2. “Acetylcholinesterase – An Overview.” ScienceDirect Topics.
Image Courtesy:
1. “Acetylcholinesterase Mechanism attempt 2” By Aparadys – ChemDraw (CC BY-SA 3.0) via Commons Wikimedia
2. “2pm8” By Deposition authors: Ngamelue, M.N., Homma, K., Lockridge, O., Asojo, O.A.; visualization author: User:Astrojan – (CC BY 3.0) via Commons Wikimedia