Regulatory effects of polyamines on membrane-bound acetylcholinesterase

The effects of putrescene, spermidine and spermine on membrane-bound acetylcholinesterase from human erythrocyte ;ghosts' and the solubilized enzyme of the electric organ of the electric eel were studied by kinetic methods. Measurements were made by using a photometric method which made it possible to record the enzyme reaction in the steady-state phase. Substrate-concentration-dependent activation and inhibition of acetylcholinesterase by polyamines is similar to that by Na(+), K(+), Ca(2+), Mg(2+) and certain quaternary and bisquaternary amines. The kinetics suggest an allosteric reaction mechanism. On the basis of the kinetic results a role for the polyamines as modulators of synaptic acetylcholinesterase is proposed.