title: Bovine nucleus caudatus acetylcholinesterase: active site determination and investigation of a dimeric form obtained by selective proteolysis.
abstract: The number of catalytic subunits of purified bovine nucleus caudatus acetylcholinesterase (E.C. 3.1.1.7) has been determined by active site labelling with [3H]diisopropyl fluorophosphate ([3H]DFP). The 10.5 S, 16 S, and 20 S forms were estimated to contain two, four, and six active sites, respectively, per molecule. A 4.8 S form, which showed a weak amphiphile-dependent activity behavior, was obtained by selective proteolytic digestion with pronase. The inability of the purified 4.8 S form to aggregate after detergent removal, and the molecular mass in the range of 130-165 kD under nondenaturating conditions, indicate that this form is a dimeric form, lacking those hydrophobic regions responsible for aggregation.
mesh_terms: D000110:Acetylcholinesterase / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002421:Caudate Nucleus / Q000201:enzymology*; D007531:Isoflurophate; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D014316:Tritium
chemical_list: D046911:Macromolecular Substances; D010446:Peptide Fragments; D014316:Tritium; D007531:Isoflurophate; D000110:Acetylcholinesterase