Ionic strength dependence of the inhibition of acetylcholinesterase activity by Al3+.
Inhibition of acetylcholinesterase activity by Al3+ has been examined by initial velocity kinetics and by a first-order kinetic method. Both methods yield an inhibition constant of approx. 1.7 mM at 0.1 M ionic strength. The initial velocity study indicates a noncompetitive mechanism of inhibition by Al3+. Inhibition at 10 mM ionic strength shows a Ki of 0.03 mM. Evaluation of the ionic strength dependence concurs with the results of Nolte et al. (Biochemistry 19 (1980) 3705). An effective charge in the binding site of -9 predicts the ratio of inhibition constants at high and low ionic strength. Extrapolation to zero ionic strength gives a Ki0 = 0.34 microM.
D000110:Acetylcholinesterase / Q000378:metabolism*; D000535:Aluminum / Q000494:pharmacology*; D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D000818:Animals; D002412:Cations; D002712:Chlorides; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D004557:Electric Organ / Q000201:enzymology; D004593:Electrophorus; D007700:Kinetics; D009994:Osmolar Concentration; D012996:Solutions
D017607:Aluminum Compounds; D002412:Cations; D002712:Chlorides; D002800:Cholinesterase Inhibitors; D012996:Solutions; D000077410:Aluminum Chloride; D000535:Aluminum; D000110:Acetylcholinesterase