title: The number of catalytic sites in acetylcholinesterase.
abstract: By using two methods of titration, the number of active sites in acetylcholinesterase was determined. Either stepwise inhibition of the enzyme by an irreversible inhibitor, namely di-isopropyl phosphorofluoridate, or direct measurement of the concentration of active sites by titration with o-nitrophenyl dimethylcarbamate yielded an equivalent weight of approx. 130000 for an active site in acetylcholinesterase. This indicates two sites per molecule, since the native enzyme has a molecular weight of 260000.
mesh_terms: D000110:Acetylcholinesterase; D001665:Binding Sites; D002219:Carbamates; D002800:Cholinesterase Inhibitors; D007531:Isoflurophate / Q000494:pharmacology; D008970:Molecular Weight; D009596:Nitrophenols
chemical_list: D002219:Carbamates; D002800:Cholinesterase Inhibitors; D009596:Nitrophenols; D007531:Isoflurophate; D000110:Acetylcholinesterase