Esterase with broad substrate specificity. Contributes to the inactivation of the neurotransmitter acetylcholine. Can degrade neurotoxic organophosphate esters. an acylcholine + H2O = a carboxylate + choline + H(+) Homotetramer; disulfide-linked. Dimer of dimers (By similarity). Present in most cells except erythrocytes. No visible phenotype; due to the presence of other cholinesterases. Hypersensitive to acetylcholinesterase inhibitors, such as huperzine and donepezil. Treatment with the acetylcholinesterase inhibitor donepezil causes convulsions and death within 3 hours of dosing. Belongs to the type-B carboxylesterase/lipase family.