IMPROVED PROPERTIES OF BOVINE ERYTHROCYTE ACETYLCHOLINESTERASE, ISOLATED BY PAPAIN CLEAVAGE

A simple and rapid procedure involving papain cleavage of the membrane anchor was used to isolate membrane-bound acetylcholinesterase from b ovine erythrocytes. The solubilized enzyme was purified 930-fold by io n exchange chromatography and gel filtration. The properties of the pa pain-cleaved acetylcholinesterase were compared with those of a commer cial acetylcholinesterase, solubilized from the erythrocyte membranes by detergents. Cleavage of the membrane anchor eliminated dimer aggreg ation, caused a pH shift in thermal stability and resulted in increase d stability in organic solvents. Bovine serum albumin, used as stabili zer of the commercial enzyme preparation, increased the thermal stabil ity but concomitantly decreased the activity of acetylcholinesterase a t pH 6-8. The improved stability of the cleaved acetylcholinesterase, especially in organic solvents, may enhance the biosensor performance of the enzyme.