PT - JOURNAL ARTICLE AU - GABOR KATO TI - Acetylcholinesterase DP - 1972 Sep 01 TA - Molecular Pharmacology PG - 582--588 VI - 8 IP - 5 4099 - http://molpharm.aspetjournals.org/content/8/5/582.short 4100 - http://molpharm.aspetjournals.org/content/8/5/582.full SO - Mol Pharmacol1972 Sep 01; 8 AB - A 60-MHz nuclear magnetic resonance method was used to study the binding of acetylcholine to acetylcholinesterase (EC 3.1.1.7). Changes in the linewidth of the N-methyl resonance of acetylcholine as a function of time, resulting from association with the enzyme during hydrolysis, were utilized to study the enzyme-substrate interaction. The resonance of the acetate protons of acetylcholine at 132 Hz (downfield from external tetramethylsilane) disappears during hydrolysis, while a new peak, due to newly formed sodium acetate, appears at 118 Hz. The rate of appearance of the free acetate peak was used to measure the initial velocity of the reaction. In the presence of high concentration of substrate (16.7 mM), eserine and neostigmine decrease substrate hydrolysis by inhibiting its binding to the enzyme. Under the same conditions atropine, (-)-hyoscyamine, and hyoscine accelerate hydrolysis of the substrate without interfering with its binding.