Electrophorus Electricus Acetylcholinesterases; Separation and Selective Modification by Collagenase¹,²

The multiple forms of acetylcholinesterase found in the electric organ of the eel Electrophorus electricus have been fractionated by differential solubilization from an ammonium sulfate precipitate by means of a column elution procedure (K ing , 1972). This procedure cleanly separates ‘native’ forms from ‘degraded’ forms, and subsequent sedimentation reveals three native and two degraded forms. All three native forms, in distinction to the degraded ones, are insoluble at low ionic strength and are shifted to higher sedimentation constants by limited collagenase treatment. These results suggest that the long (500 Á) tail seen previously on the native forms of this enzyme (D udai et al ., 1973; R ieger et al ., 1973 a, b ) may contain collagen.