AChE / BChE
Definition
Acetylcholinesterase (RBC membrane bound, true cholinesterase) and butyrylcholinesterase (plasma, pseudo-cholinesterase). Both depressed in OP and carbamate exposure; plasma BChE falls first and recovers first, RBC AChE tracks long-term inhibition.
- Enzyme type
- AChE is true cholinesterase, BChE is pseudo-cholinesterase
- AChE location
- Red blood cell membrane
- BChE location
- Blood plasma
- Recovery order
- Plasma BChE falls and recovers first
- Exposure marker
- Both depressed by organophosphate and carbamate poisoning
Common questions
Why measure both AChE and BChE in suspected organophosphate poisoning?+
BChE responds faster and gives an early warning of exposure, while RBC AChE better reflects synaptic inhibition and is used to judge severity and recovery over the following weeks, since it regenerates only as new red cells are made.
Does a normal BChE level rule out organophosphate poisoning?+
No. BChE can normalize within days while RBC AChE remains depressed for weeks, so a normal plasma BChE alone does not exclude a significant recent organophosphate exposure.
Related terms
- Aluminium Phosphide (AlP)
- Solid grain-fumigant rodenticide sold as Celphos, Quickphos, Sulfas tablets. On contact with moisture or stomach acid, releases phosphine (PH3) gas, which blocks...
- Carbamate
- Carbamic-acid ester insecticides (carbaryl, carbofuran, propoxur, aldicarb). Reversibly inhibit acetylcholinesterase by carbamylating the active-site serine; spontaneous decarbamylation makes oximes unnecessary and sometimes...
- Ellman Method
- Standard spectrophotometric cholinesterase assay. Acetylthiocholine substrate plus 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) yields a yellow 5-thio-2-nitrobenzoate anion read at 412 nm. The rate of...
- Organochlorine (OC)
- Chlorinated hydrocarbon insecticides (DDT, BHC/lindane, endosulfan, dicofol, aldrin, dieldrin). Highly lipophilic, neurotoxic via voltage-gated sodium channel disruption, and persistent in fat and...
- Organophosphate (OP)
- A class of insecticides (monocrotophos, chlorpyrifos, methyl parathion, dichlorvos, phorate) that inhibit acetylcholinesterase, producing the cholinergic toxidrome. The dominant suicidal poison in...
- Pyrethroid
- Synthetic analogues of natural pyrethrins (deltamethrin, cypermethrin, permethrin, fenvalerate). Act on voltage-gated sodium channels like OC but break down quickly in mammals,...
- QuEChERS
- Quick, Easy, Cheap, Effective, Rugged and Safe sample-prep protocol for pesticide residues. Acetonitrile extraction, MgSO4 + NaCl partition, dispersive SPE clean-up with...