Comparative Studies on the Molecular Properties of Purified Acetylcholinesterase from Human Erythrocytes and from the Electric Organ of Electrophorus electricus

Acetylcholinesterases from human erythrocytes and from the electric organ of Electrophorus electricus were purified by affinity chromatography to high degrees of purity. The molecular parameters of both enzymes were compared following density gradient centrifugation, gel filtration, i.soelectric focusing and polyacrylamide gel electrophoresis. Sucrose density gradient centrifugation revealed that the human enzyme exists in a more complex state of aggregation than the eel enzyme. Upon isoelectric focusing both enzymes could be resolved into multiple molecular forms; the eel enzyme however focused at a lower pH than the red cell enzyme. The Stokes radii of the human enzyme forms range between 6.8 and 12.9 nm; the ones for the eel enzyme forms are between 6.4 and 15.0 nm. SDS ~polyacrylamide gel electrophoresis gave one subunit only for both enzymes with apparent molecular weights of 80 000 and 93 000 for the human and the eel enzyme respectively