Hydrolyzes rapidly the acetylcholine neurotransmitter released into the synaptic cleft allowing to terminate the signal transduction at the neuromuscular junction. Role in neuronal apoptosis. acetylcholine + H2O = acetate + choline + H(+) Interacts with PRIMA1. The interaction with PRIMA1 is required to anchor it to the basal lamina of cells and organize into tetramers (By similarity). Isoform H generates GPI-anchored dimers; disulfide linked. Isoform T generates multiple structures, ranging from monomers and dimers to collagen-tailed and hydrophobic-tailed forms, in which catalytic tetramers are associated with anchoring proteins that attach them to the basal lamina or to cell membranes. In the collagen-tailed forms, isoform T subunits are associated with a specific collagen, COLQ, which triggers the formation of isoform T tetramers, from monomers and dimers. Isoform R may be monomeric. Only observed in apoptotic nuclei. Isoform H is highly expressed in erythrocytes. ACHE is responsible for the Yt blood group system [MIM:112100]. The molecular basis of the Yt(a)=Yt1/Yt(b)=Yt2 blood group antigens is a single variation in position 353; His-353 corresponds to Yt(a) and the rare variant with Asn-353 to Yt(b). Belongs to the type-B carboxylesterase/lipase family. Blood group antigen gene mutation database Acetylcholinesterase entry