Esterase with broad substrate specificity. Contributes to the inactivation of the neurotransmitter acetylcholine. Can degrade neurotoxic organophosphate esters (By similarity). an acylcholine + H2O = a carboxylate + choline + H(+) Homotetramer; disulfide-linked. Dimer of dimers (By similarity). Present in most cells except erythrocytes. Belongs to the type-B carboxylesterase/lipase family.