Activating Proteins for Ganglioside GM2Degradation by β-Hexosaminidase Isoenzymes in Tissue Extracts from Different Species

Abstract

The existence of activator proteins that stimulate hydrolysis of ganglioside GM2 by .beta.-hexosaminidase was demonstrated in kidney extracts from 4 species (rat, mouse, cattle and pig). The extent to which these preparations, as well as their human counterpart, promote ganglioside GM2 catabolism by autologous and heterologous hexosaminidase isoenzymes was compared. These activators can replace each other functionally, although the animal activator proteins do not cross-react immunochemically with an antiserum against the human protein. All preparations examined catalyzed the transfer of ganglioside GM2 between liposomal membranes, indicating that the animal activator proteins act by a mechanism similar to the human GM2 activator.