Rapidly hydrolyzes choline released into the synapse. acetylcholine + H2O = acetate + choline + H(+) Strain SLAB is susceptible to insecticides while strain SR is resistant. Insensitivity to insecticides results from a loss of sensitivity of acetylcholinesterase to organophosphates and carbamates and is due to a variant at position 247. Belongs to the type-B carboxylesterase/lipase family.