title: Glycolipid membrane-binding domain of human erythrocyte acetylcholinesterase.
abstract: The membrane-binding domain of human erythrocyte acetylcholinesterase is a small hydrophobic structure at the COOH-terminus of the enzyme subunits. Papain digestion cleaves a COOH-terminal dipeptide linked to the hydrophobic structure with the sequence His-Gly-ethanolamine-Z, where the ethanolamine is in amide linkage to the glycine and Z is a partially characterized glycolipid. This glycolipid includes a second residue of ethanolamine and a residue of glucosamine, both of which have free primary amino groups accessible to radiomethylation. The glycolipid also contains a carbohydrate residue or residues that bind to concanavalin A and nearly stoichiometric amounts of both palmitate and C22 unsaturated fatty acids. Similarities in this membrane-binding structure to those reported for trypanosome variant surface glycoproteins and Thy-1 glycoprotein suggest an important new category of posttranslational modifications involving the attachment of COOH-terminal glycolipid.
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood*; D000595:Amino Acid Sequence; D001665:Binding Sites; D002241:Carbohydrates / Q000032:analysis; D004912:Erythrocytes / Q000201:enzymology*; D005227:Fatty Acids / Q000032:analysis; D006017:Glycolipids / Q000097:blood*; D006801:Humans; D008565:Membrane Proteins / Q000097:blood*; D010206:Papain; D010446:Peptide Fragments / Q000097:blood
chemical_list: D002241:Carbohydrates; D005227:Fatty Acids; D006017:Glycolipids; D008565:Membrane Proteins; D010446:Peptide Fragments; D000110:Acetylcholinesterase; D010206:Papain