AbstractBasal lamina (BL) ofTorpedo,DiscopygeandElectrophoruselectric organs was purified in order to establish polypeptide composition and association with acetylcholinesterase (AChE). Results indicate that BL presents a distinct peptide pattern and that the A12form of AChE is directly attached to it. Comparison of the species studied demonstrated similarities both in polypeptide composition and AChE content of the purified BL. Extractions of BL with solutions of high ionic strength, guanidine–HCl and acetic acid indicated the differential solubilization of various domains of BL polypeptide