Mammalian brain acetylcholinesterase (AChE; EC 3.1.1.7) is membrane-bound through a structural subunit of about 20 kDa. So far little is known about this anchor because it is only detectable after hydrophobic labelling. In the present study we demonstrate that the two bands migrating around 20 kDa on SDS-PAGE derive from the same protein containing the same N-terminal amino acid sequence. The difference in their mobility is due to different N-glycosidation. Radioalkylation of cysteine residues reveals that the anchor contains just the two cysteine residues involved in binding the catalytic subunits.
