title: Characterization of Hex S, the major residual beta hexosaminidase activity in type O Gm2 gangliosidosis (Sandhoff-Jatzkewitz disease).
abstract: Hex S, the major residual beta hexosaminidase activity present in tissues, fluids, and cultured skin fibroblasts of patients with type 0 GM2 gangliosidosis, was isolated and characterized biochemically and immunologically. when appropriate tissue homogenates were tested by electrophoresis on cellulose acetate gels, hex S as well as hex C, the corresponding minor beta hexosaminidase component found in normal visceral tissues, migrated with greater anodic mobilities than hex A. However, a small but reproducible electrophoretic difference was observed between partially purified hex S and hex C components. Hex S and hex C had slightly higher apparent molecular weights than those of hex A or hex G; no major differences were found between hex S and hex A in thermostability, pH optimum, or kinetic properties. Hex S, like hex C from placenta, reacted with an antiserum directed towards the unique antigenic determinants alpha of hex A, indicating that hex S, hex C, and hex A share a common antigenic determinant. No reactivity of hex S was detected with an antiserum directed toward the common antigenic determinant beta of hex A and hex B. These results suggest that further biochemical and immunologic characterization of hex S and elucidation of its relationships with hex A, hex B, and hex C may significantly contribute to the understanding of the molecular defects in the GM2 gangliosidoses.
mesh_terms: D001923:Brain Chemistry; D002852:Chromatography, Ion Exchange; D004586:Electrophoresis; D004791:Enzyme Inhibitors; D005733:Gangliosidoses / Q000235:genetics*; D006596:Hexosaminidases / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000032:analysis; D008099:Liver / Q000032:analysis; D008168:Lung / Q000032:analysis; D008970:Molecular Weight; D009206:Myocardium / Q000032:analysis; D013154:Spleen / Q000032:analysis; D013577:Syndrome
chemical_list: D004791:Enzyme Inhibitors; D006596:Hexosaminidases