The action of trypsin and neuraminidase on the synaptic membranes of brain cortex

Abstract

The population of intracellular membranes of rat cerebral cortex which exhibited the highest relative specific concentration of bound N- acetylneuraminic acid (NANA) and the highest relative specific activity of acetylcholinesterase (EC 3.1.1.7) (synaptic membranes) was incubated with bacterial neuraminidase and with trypsin under a number of experimental conditions. The electrokinetic profile displayed by the membrane preparation upon zonal density gradient electrophoresis changed as a result of the removal of bound NANA by neuraminidase, while its acetylcholinesterase activity remained unaffected; conversely, the action of trypsin led to the inactivation of acetylcholinesterase before any significant alterations of the electrophoretic mobility of the membranes became apparent. Prolonged incubation alone or in the presence of either neuraminidase or trypsin, resulted in the loss of membrane electrophoretic homogeneity, a circumstance which, most likely, reflects a disaggregation of the structural matrix of the membrane.