The number of catalytic sites in acetylcholinesterase

Biochem J. 1971 Jun;123(2):139-41. doi: 10.1042/bj1230139.

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

  • Acetylcholinesterase*
  • Binding Sites*
  • Carbamates
  • Cholinesterase Inhibitors
  • Isoflurophate / pharmacology
  • Molecular Weight
  • Nitrophenols

Substances

  • Carbamates
  • Cholinesterase Inhibitors
  • Nitrophenols
  • Isoflurophate
  • Acetylcholinesterase