An ESR study of the influence of some physico-chemical factors on the conformation of a postsynaptic acetylcholinesterase.
1. In a previous ESR study of a membrane acetylcholinesterase (EC 3.1.1.7) we found, contrary to observations by other authors, spectra indicating that the active serine might be located in a pocket of the enzyme surface. In order to inquire into this possibility, ESR spectra were studied under the influence of different physico-chemical factors known to cause an unfolding of proteins. 2. The active serine of the postsynaptic membrane acetylcholinesterase of Torpedo marmorata electric organ was spin labeled using 1-oxyl-2, 2, 6, 6-tetramethyl-4-piperidinyletoxyphosphonofluoridate. 3. The effect of the chosen physico-chemical factors was an increase in the rotational freedom of spin labels; this result corroborates the suggestion that the active center of our acetylcholinesterase preparation is located in a pocket.
D000110:Acetylcholinesterase; D000818:Animals; D004557:Electric Organ / Q000201:enzymology*; D004578:Electron Spin Resonance Spectroscopy; D005399:Fishes; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008566:Membranes / Q000201:enzymology; D011487:Protein Conformation; D013113:Spin Labels; D013569:Synapses / Q000201:enzymology*; D014508:Urea
D013113:Spin Labels; D014508:Urea; D000110:Acetylcholinesterase