The C-terminal t peptide (40 residues) of vertebrate acetyl-cholinesterase (AChE) T subunits possesses a series of seven conserved aromatic residues and forms an amphiphilic a-helix; it allows the formation of homo-oligomers (mono-mers, dimers and tetramers) and heteromeric associations with the anchoringproteins, ColQ and PRiMA, which contain a proline-rich motif (PRAD). We analyzed the influenceofmutations in the t peptideofTorpedoAChETon oligomerization and secretion.