Erythrocyte hypotonic lesion stimulates plasmalemmal acetylcholine esterase

Contrary to the rather high amount of acetylcholine esterase, histochemical methods revealed only an insignificant activity of that enzyme in the erythrocyte plasmalemma. Following hypotonic incubation many damaged red cells whether or not hemolyzed were heavily loaded with reaction products on the outer aspect of their membrane. The findings are consistent with a suggested allosteric activation of acetylcholine esterase in the moderately disintegrated cell membrane. Thus, the cytochemical demonstration of acetylcholine esterase is considered a means to assess the plasmalemmal integrity of individual red cells.