According to a recent hypothesis, glycosphingolipids originating from the plasma membrane
are degraded in the acidic compartments of the cell as components of intraendosomal and
intralysosomal vesicles and structures. Since most previous in vitro investigations used
micellar ganglioside GM2 as substrate, we studied the degradation of membrane-bound
ganglioside GM2 by water-soluble β-hexosaminidase A in the presence of the GM2 activator
protein in a detergent-free, liposomal assay system. Our results show that anionic lipids such …